US-UK Mutual Defence Agreement A Nuclear Information Service Briefing 1 2 US-UK Mutual Defence Agreement A Nuclear Information Service Briefing Nuclear Information Service July 2024 3 NIS Contents Nuclear Information Service (NIS) is an independent, Introduction 5 not-for-profit research organisation, founded in 2000. History of the MDA 6 We investigate the UK nuclear weapons programme The Treaty 8 and publish accurate and reliable information to Legality 8 stimulate informed debate on disarmament and Activities under the MDA 10 related issues. Nuclear Testing 10 Transfer of nuclear material 11 Transfer of non-nuclear components 11 Joint Working Groups and Secondment 12 Future of the MDA 13 Annotated Treaty text 16 Endnotes 24 4 Introduction This briefing gives an overview of the Agreement between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the United States of America for Cooperation on the Uses of Atomic Energy for Mutual Defense Purposes, commonly known as the Mutual Defence Agreement (MDA). The MDA is the treaty that governs the relationship between the nuclear weapons programmes of the United Kingdom (UK) and United States (US), which is unique amongst nuclear armed states for the level of dependency and technical integration involved. The treaty allows for the exchange of information about nuclear technologies between the two states, and for the US to provide the UK with nuclear materials, such as uranium and plutonium, components of nuclear weapons, and submarine reactor technology. Staff from the nuclear enterprises in both countries coordinate activities through Joint Working Groups and are sometimes seconded to work in the other country for some time. Until 1992, cooperation under the MDA included use of each others’ sites for nuclear testing, particularly the UK testing nuclear weapons in Nevada. 5 lGO/llirreM nAiluJ )tOHP(AOP :tiderC The UK currently operates a submarine-launched nuclear weapons system. The reactors that power the UK’s four nuclear-armed submarines, and other submarine technologies on board, are based on US designs. The UK’s warheads are believed to be very close in design to weapons in the US stockpile. US designed and manufactured Trident missiles carry the UK’s warheads. The UK’s use of the Trident system is governed by an updated version of the Polaris Sales Agreement, which is a separate treaty from the MDA. In 2014 David Lidington, a UK Foreign Office Minister, said the treaty ‘helps to provide the maintenance and servicing required to ensure the safety, security and reliability’ of the UK’s nuclear weapons ‘at a substantial reduction on the costs that would otherwise be incurred’.1 Sharing of nuclear material and other components under the MDA is due to be extended for 10 years before the end of 2024. HMS Victorious, one of the UK’s nuclear-armed submarines, alongside at Faslane in 2007. History of the MDA2 The UK and US worked together on the Manhattan uranium 235 for civil use, more intelligence sharing Project, which produced the first nuclear weapons. and joint nuclear war planning. Uranium 235 is the The basis for nuclear cooperation during the Second highly radioactive isotope used in reactor fuel and World War was the 1943 Quebec Agreements and the nuclear weapons. An agreement on the UK being 1944 Hyde Park aide memoire. Both were executive supplied with nuclear submarine technology followed agreements between Churchill and Roosevelt, rather in 1956. than treaties, and were not subject to Congressional approval. The UK’s production capacity for aircraft capable of carrying nuclear weapons soon outstripped the speed After the use of nuclear weapons in Hiroshima and at which it could produce nuclear material for the Nagasaki, the US Congress, which was not aware weapons themselves. Informal discussions began in of the extent of UK involvement in the Manhattan 1957 on the US providing highly enriched uranium Project, passed the 1946 McMahon Act. The act (HEU) to allow the UK to increase its stockpile faster, prevented US citizens from sharing information about although the transfers were not permitted under the nuclear weapons with foreign nationals, immediately 1954 Act. curtailing cooperation with the UK.3 The UK’s nuclear weapons at this time were all Due to differing interpretations of the Act amongst US fission designs, utilising the destructive power of a government agencies some collaboration on intelligence critical mass of fissile material, compressed using sharing and uranium supply continued to take place. As explosives. Modern US and UK weapon designs are the Cold War began to take hold, US nuclear bombers thermonuclear weapons where the energy from a were also deployed in the UK, and the practicalities of fission weapon, made of uranium 235 or plutonium, military cooperation would in time place a strain on the is used as a ‘primary’ to implode a ‘secondary’: a fuel strict conditions of the McMahon Act. which undergoes nuclear fusion, releasing an even greater destructive power. The UK had responded to the Act by deciding to develop its own nuclear weapons. The US, at the time The UK producing its own independent thermonuclear still the only nuclear-armed state, made a proposal weapons is often portrayed as the trigger for the in 1948 for a resumed integrated nuclear weapons US deciding that it was willing to resume nuclear programme which would have seen the UK having cooperation,4 but this is not the case. The UK carried custody of a stockpile of 20 nuclear bombs. A similar out tests on thermonuclear weapons in May and June proposal was floated in 1953, following the UK’s first 1957, but the tests were not successful. At the time nuclear test in 1952, but the two states did not come to the US was publicly calling for an international ban an agreement. The UK was the third state to develop on both nuclear testing and the further production its own nuclear weapons, the Soviet Union having of nuclear weapons, in response to domestic and carried out a nuclear test in 1949. international protests against atmospheric testing. The UK was keen to produce a working thermonuclear In 1954 the McMahon Act was replaced with the design before this happened. After the thermonuclear Atomic Energy Act, a compromise which allowed tests failed the UK told the US it would only support exchanges of knowledge for civil nuclear purposes the proposed ban if it had independent access to a and allowed some basic information about the yields stockpile of modern weapon designs. and military characteristics of US nuclear weapons to be shared with NATO states. This would allow these The launch of the Sputnik satellite in October 1957 states, including the UK, to field delivery systems changed the political environment, as it demonstrated for the weapons. A new UK-US agreement in 1955, that Soviet rocket technology could theoretically brokered under the new regime, covered the supply of launch a nuclear weapon as far as the continental 6 Canadian Prime Minister Mackenzie King, President Franklin D Roosevelt and Winston Churchill during the Quebec Conference, 18 August 1943. Canada hosted the conference but was not party to the Quebec Agreement. US. A US-UK leaders’ summit was quickly arranged, were set aside to allow matters to progress. President which resulted in the US National Security Council Eisenhower eventually signed an updated Atomic approving a full exchange of information and a Energy Act in July 1958 and the MDA was signed the commitment from the US to amend the 1954 Act. following day. While discussions were ongoing about the shape of future cooperation, the UK carried out a successful test The treaty has been repeatedly amended, often to of a thermonuclear design in November 1957. extend the time period for sharing nuclear material and non-nuclear components, but there have been The MDA reflected the priorities of both states, but several amendments that demonstrate that it is it more closely resembles the form envisaged by the a living document, regularly updated to reflect US at the beginning of negotiations. Congressional the realities of the working relationship. Regular hearings on amending the 1954 Act began in early 1958, ‘stocktake’ meetings are held to discuss and plan the but controversies around an exchange of plutonium functioning of the treaty.5 and HEU, and a proposal for nuclear warheads under joint US-UK control, meant that these measures 7 MuesuM rAW lAirePMi :tiderC The Treaty Legality The initial form of the treaty allowed for the sharing A 2004 legal advice prepared by Rabinder Singh of intelligence and sale of a submarine reactor and QC and Professor Christine Chinkin said it was fuel to the UK, covered in Article II and Article III of the ‘strongly arguable’ that the role of the MDA in the treaty respectively. Despite its prominence in bilateral UK’s ongoing nuclear weapons programme was a discussions leading up to the treaty, the transfer of breach of the country’s obligations under the Nuclear complete nuclear weapons between the two states was Non-Proliferation Treaty (NPT), under which the explicitly prohibited in the treaty text. An amendment nuclear-armed states agreed to eliminate their nuclear to the treaty in 1959 added Article III bis, which enabled weapons.11 the transfer of nuclear material and non-nuclear components of nuclear weapons, but initially only The position of the UK government, as stated in a 2014 for a 10-year period. Most of the amendments to the parliamentary debate, is that the MDA does not breach treaty have extended this period, and since 1984 the the NPT because it prohibits transfer of complete extensions have been for additional periods of 10 years. nuclear weapons and only allows for the transfer of knowledge and weapon components between two Other amendments have made more substantial nuclear-weapon states. At the time it was also stated changes to the treaty. In 1984, the first amendment that the UK was complying with its obligations under after the US sale of the Trident missile system to the the NPT by reducing the numbers of its nuclear UK had been agreed, text was added enlarging the weapons.12 However, since then government policy has scope of information sharing under the treaty and changed and in 2021 a planned reduction in the UK’s to allow for the transfer of enriched uranium for any stockpile to 180 warheads was reversed and instead the purpose.6 In 2014 the amendments added a reference stockpile size was increased to 260.13 to the dangers of proliferation in the preamble, and allowed for the UK to purchase more submarine reactors, reactor parts and fuel.7 Smaller amendments have also been made, for example in 1994 a change was made to allow the US to arrange uranium enrichment for the UK, rather than directly providing it.8 In 1979 a paragraph was added to stipulate that sharing under the agreement should be for defence purposes in the mutual interests of the two states,9 but in 2014 this paragraph was amended to state that these purposes include evaluating the capabilities of enemy states.10 An annotated copy of the key treaty sections in their current form can be found on page 16 of this briefing. The treaty is written using US English spellings, and contains some stylistic inconsistencies arising from amendments over the years. Article IX, which deals with intellectual property issues, and Article X, which brings earlier cooperation between the two states under the terms of the MDA, have not been included for reasons of space. Neither article has been substantially Facing page: amended since the original treaty was signed. Mushroom cloud from the US Dominic Truckee nuclear test, 9 June 1962, Kiritimati. 8 seviHCrA lAnOitAn su 9 seviHCrA lAnOitAn su Nuclear Testing Although one of the drivers for the treaty was concern about a ban on nuclear testing,14 access to testing facilities was one of the UK’s priorities in the original negotiations. After the 1958 moratorium on nuclear testing was breached by the USSR in 1961, the UK and US both resumed testing, with the UK carrying out tests at the Nevada Test Site (NTS), and the US carrying out most of their Dominic test series in Kiritimati (then known as ‘Christmas Island’),15 which was at that time a British colonial holding. The UK carried out 24 underground tests at the NTS between 1962 and 1991. The final test, known as ‘Julin/ Bristol’, is believed to have been testing the lower-yield variant of the UK Trident warhead.16 The US Dominic test series involved 25 atmospheric nuclear tests at or near Kiritimati.17 Indigenous people in both Nevada18 and Kiritimati,19 and armed forces veterans,20 are still dealing with the consequences of nuclear tests. Craters from underground nuclear tests at Yucca Flat, in the Nevada Test site. 10 Asnn :tiderC Activities under the MDA Since 1992 both states have observed a moratorium on nuclear testing and have signed the Comprehensive Nuclear Test Ban Treaty, however the US has not ratified the treaty. Both the UK and US have active development and research programmes and are upgrading their nuclear weapons systems. This work does not involve live testing of nuclear weapons, but instead research using high energy lasers, computer simulation and sub-critical tests, which only use smaller quantities of fissile material than the amount needed to reach a critical mass. Through the MDA the UK and US research programmes are deeply intertwined and many of their research facilities have been designed to be complementary.21 The vast majority of countries worldwide have expressed concerns about countries upgrading their nuclear weapons.22 Figure A. Transfer of non-nuclear components under the MDA 2020–2023 Calendar year Transfers from US to UK (single items) Transfers from UK to US (single items) 2020 128 14 2021 271 25 2022 302 31 2023 254 38 Total 955 108 Transfer of nuclear material Transfer of non-nuclear components The acquisition of nuclear material from the US was There is little information in the public domain about a major initial goal for the UK, and the purchase of the quantity and nature of transfers of non-nuclear HEU for submarine reactors and tritium for nuclear components under the MDA. It is known that the weapons took place soon after the treaty was signed. Mk4A upgrade to the UK’s nuclear warhead, completed Subsequently, barter exchanges of nuclear material in 2023, involved changing the arming, fusing and were carried out between 1960 and 1979, with the UK firing system, neutron initiators and the gas transfer sending plutonium in exchange for HEU and tritium. system, with these components being imported The UK sent 0.5 tonne of plutonium to the US between from the US.25 The submarine reactor used in the 1960 and 1969 under Barter A, 4.1 tonnes between 1964 current Astute and Vanguard nuclear submarines is and 1969 under Barter B and 0.8 tonne between 1975 and a UK-specific design and may only use domestically 1979 under Barter C. In return, the UK received a total of produced parts. However, the PWR3 reactor used in 6.7kg of tritium and 7.5 tonnes of HEU from the US.23 the forthcoming Dreadnought submarines is based on a US design26 and it is possible that some parts for Transfers of plutonium also took place outside of these reactors are being imported under the MDA. these disclosed barter arrangements, with a total of 0.47 tonne being sent from AWE Aldermaston to the In response to a Freedom of Information Request US and received back prior to March 1999. The timing by NIS the MOD stated that transfers of non- of these plutonium ‘loans’ and in which direction the nuclear parts of nuclear weapon systems under the initial transfer took place has not been disclosed.24 MDA between 2020 and 2023 had amounted to 955 individual items being transferred from the US to the No information about plutonium transfers after UK and 108 individual items being transferred from March 1999 or transfers of HEU and tritium outside the UK to the US.27 The breakdown of these transfers the three barter exchanges has been made public, by year can be found in Figure A. and the MOD has rejected Freedom of Information Requests for information about more recent transfers. However, the 2014 amendments to the MDA and nuclear road convoy movements suggest that transfer of HEU fuel for UK submarines is ongoing. The UK and US also have a joint programme to calibrate their nuclear forensic laboratories by testing the same samples, and the transfer of nuclear material in these samples is likely also carried out under the MDA. 11 Joint Working Groups and Secondment The primary method for US-UK cooperation under the MDA is through Joint Working Groups (JOWOGs). These are thematic committees comprised of subject matter experts from the nuclear enterprises of both countries. Each JOWOG focusses on a particular research area that has been identified during stocktake meetings and meets periodically. JOWOG meetings include presentations on specific areas of research, but can also agree research priorities, review progress and determine how work should be divided between Warhead handling during the US W76-1 warhead upgrade, different agencies or laboratories. which involved many components used in the UK Mk4A upgrade. Figure B shows the activity of JOWOGs since 1959. Initially 15 JOWOGs were created, but most of these have been retired as their remit was no longer deemed relevant. At least 48 JOWOGs have been created since 1959, and 15 are currently active, as of June 2024.28 Some JOWOGs appear to have been retired and reactivated at a later date, but this seems to be comparatively rare. Some of the JOWOGs have subcommittees for further specialisation within the subject area. These are known as SUBWOGs. Figure B shows the JOWOGs known to have been active at different times during the operation of the MDA. Of the original 15, only one is known to still be active: JOWOG 9, which coordinates research on ‘Energetic Materials’, meaning explosives. Some JOWOGs have undergone name changes over the years. The titles of two of the original 15 JOWOGs have been partially redacted. The full title of JOWOG 2 appears to have been ‘500 to 600-pound megaton warhead’.29 Of the 15 JOWOGs currently active, the MOD refused to disclose the names of six.30 As a consequence it is not clear whether the JOWOGs looking into ‘Radiation Simulation and Kinetic Effects’, ‘Warhead Electrical Components and Technologies’, ‘Nuclear Counter- Terrorism Technology’, ‘Aircraft, Missile and Space System Hardening’, and ‘Methodologies for Nuclear Weapon Safety Assurance’ are still active. The title of JOWOG 47 has not been made public,31 and it can be surmised that at least one other new JOWOG has been created since 2009. One or more of these new groups are probably working on the planned 12 tnAlP xetnAP :tiderC new US W93 and UK Astrea warheads, which have been described as ‘parallel’ projects, and their re-entry bodies. Aside from JOWOGs the two states also arrange Exchange of Information by Visit Report, which are one-off information exchange events and Channels, which are more often used for management coordination and the exchange of regular information.32 Between 2007 and 2009 over 2,000 visits by AWE staff were made to US nuclear facilities.33 Secondment of staff from one state to the nuclear enterprise of the other also takes place, building up reciprocal knowledge and allowing for deployment of specific expertise. In response to a Freedom of Information request in June 2024 the Atomic Weapons Establishment (AWE) said that the numbers of its employees seconded to the US and of US employees seconded to AWE was ‘very low’, so disclosing the actual numbers risked identifying individuals.34 In response to a parliamentary question in 2018 the government said that 43 employees of the US government and General Dynamics Electric Boat company were seconded with the Dreadnought programme and 20 UK government employees working on the Dreadnought programme were seconded to the US.35 Future of the MDA The 2014 amendment to the MDA extended the sunset clause for Article III bis until December 31 2024. It is expected that the two governments will agree and publish a proposed amendment that will further extend the operation of the treaty until 2034. The amendment will need to be approved by the US Congress before it can come into force. Under the 2010 Constitutional Reform and Governance Act the UK Government has to publish any treaty it plans to ratify 21 days ahead of time, and Parliament can vote to block ratification, potentially indefinitely.36 Nuclear Information Service calls on the UK Parliament to properly scrutinise amendments to the MDA through select committee hearings and/or debates, in order to ensure that any extension of the treaty is geared towards both nations fulfilling their disarmament commitments under the Nuclear Non- Proliferation Treaty, rather than avoiding them. 13 JOWOG 1959 1973 1995 1997 Antimissile missile defence 1 systems 500 to 600-pound [redacted] 2 warhead 3 150-pound [redacted] warhead Methods of predicting one-point 4 detonation yields 5 External neutron sources Neutron sources Irradiation effects on materials Irradiation effects on materials Radiation Simulation and Kinetic 6 and components and components Effects Technology 7 Mixing in gas-boosted weapons 8 Shock-initiation of explosives 9 Safety of HMX explosives Energetic Materials Nonnuclear and hydrodynamic 10 testing Analysis and specification of 11 materials* Chemistry and Compatability of 12 Compatability of materials materials Underground and outer space 13 testing 14 Weapons effects for future tests 15 Joint test facilities 16? Test Diagnostics 17? Test monitoring 18? Metallurgy of Weapons Materials 19? Non-Nuclear Components 20? Underground Effects Testing 21? Non-Metallic Materials 22 Nuclear Materials Warhead Electrical Components 23 and Technologies ? Weapons Material Management 28 Non-Nuclear Materials Nuclear Counter-Terrorism 29 Technology 30 Facilities 31 Nuclear Weapons Engineering 32 Physics Design Nuclear Warhead Physics 33 Weapons Hydrodynamics 34 Computational Technology 35 Penetration Aid Technology Aircraft, Missile and Space System 36 Aircraft Hardening Hardening 37 Nuclear Weapons Physics Laboratory Plasma Physics Nuclear Forces and Counter 38 Proliferation Studies 39 Manufacturing Technology 40 Experimental Activities 41 Nuclear Warhead Accident Response Technology Nuclear Weapon Computer Code Nuclear Weapon Code 42 Development Development 43 Nuclear Weapon Environment and Damage Effects 44 45 46 47 48 14? 734202–9591 spuorG gnikroW tnioJ evitcA .B erugiF JOWOG 1959 1973 1995 1997 JOWOG 1959 1973 1995 1997 Antimissile missile defence Antimissile missile defence 1 1 systems systems 500 to 600-pound [redacted] 500 to 600-pound [redacted] 2 2 warhead warhead 3 150-pound [redacted] warhead 3 150-pound [redacted] warhead Methods of predicting one-point Methods of predicting one-point 4 4 detonation yields detonation yields 5 External neutron sources Neutron sources 5 External neutron sources Neutron sources Irradiation effects on materials Irradiation effects on materials Radiation Simulation and Kinetic Irradiation effects on materials Irradiation effects on materials Radiation Simulation and Kinetic 6 6 and components and components Effects Technology and components and components Effects Technology 7 Mixing in gas-boosted weapons 7 Mixing in gas-boosted weapons 8 Shock-initiation of explosives 8 Shock-initiation of explosives 9 Safety of HMX explosives Energetic Materials 9 Safety of HMX explosives Energetic Materials Nonnuclear and hydrodynamic Nonnuclear and hydrodynamic 10 10 testing testing Analysis and specification of Analysis and specification of 11 11 materials* materials* Chemistry and Compatability of Chemistry and Compatability of 12 Compatability of materials 12 Compatability of materials materials materials Underground and outer space Underground and outer space 13 13 testing testing 14 Weapons effects for future tests 14 Weapons effects for future tests 15 Joint test facilities 15 Joint test facilities 16? Test Diagnostics 16? Test Diagnostics 17? Test monitoring 17? Test monitoring 18? Metallurgy of Weapons Materials 18? Metallurgy of Weapons Materials 19? Non-Nuclear Components 19? Non-Nuclear Components 20? Underground Effects Testing 20? Underground Effects Testing 21? Non-Metallic Materials 21? Non-Metallic Materials 22 Nuclear Materials 22 Nuclear Materials Warhead Electrical Components Warhead Electrical Components 23 23 and Technologies and Technologies ? Weapons Material Management ? Weapons Material Management 28 Non-Nuclear Materials 28 Non-Nuclear Materials Nuclear Counter-Terrorism Nuclear Counter-Terrorism 29 29 Technology Technology 30 Facilities 30 Facilities 31 Nuclear Weapons Engineering 31 Nuclear Weapons Engineering 32 Physics Design Nuclear Warhead Physics 32 Physics Design Nuclear Warhead Physics 33 Weapons Hydrodynamics 33 Weapons Hydrodynamics 34 Computational Technology 34 Computational Technology 35 Penetration Aid Technology 35 Penetration Aid Technology Aircraft, Missile and Space System Aircraft, Missile and Space System 36 Aircraft Hardening 36 Aircraft Hardening Hardening Hardening 37 Nuclear Weapons Physics Laboratory Plasma Physics 37 Nuclear Weapons Physics Laboratory Plasma Physics Nuclear Forces and Counter Nuclear Forces and Counter 38 38 Proliferation Studies Proliferation Studies 39 Manufacturing Technology 39 Manufacturing Technology 40 Experimental Activities 40 Experimental Activities 41 Nuclear Warhead Accident Response Technology 41 Nuclear Warhead Accident Response Technology Nuclear Weapon Computer Code Nuclear Weapon Code Nuclear Weapon Computer Code Nuclear Weapon Code 42 42 Development Development Development Development 43 Nuclear Weapon Environment and Damage Effects 43 Nuclear Weapon Environment and Damage Effects 44 44 45 45 46 46 47 47 48 48 ? ? 15 Annotated Treaty text38 The Government of the United Kingdom of Great Britain and Northern Ireland and the Reference to the United Government of the United States of America, Kingdom Atomic Energy Authority (UKAEA) C onsidering that their mutual security and defense require that they be prepared to removed in 1974. meet the contingencies of atomic warfare; C onsidering that both countries have made substantial progress in the development of atomic weapons; Reaffirmingthatthespreadofatomicweaponstechnology,potentiallyincluding  Text added to preamble State and sub-State actors, imperils the defense and security of both nations; in 2014 referencing Considering that they are participating together in international arrangements proliferation risks. pursuant to which they are making substantial and material contributions to their mutual defense and security; Recognizing that: their common defense and security will be advanced by the exchange of information concerning atomic energy and by the transfer of equipment and materials for use therein; Believing that such exchange and transfer can be undertaken without risk to the defense and security of either country; and Taking into consideration the United States Atomic Energy Act of 1954, as amended, which was enacted with these purposes in mind, Have agreed as follows: 16 ARTICLE I General Provision While the United States and the United Kingdom are participating in an international arrangement for their mutual defense and security and making substantial and material contributions thereto, each Party will communicate to and exchange with the other Party information, and transfer materials and equipment to the other Party, in accordance with the provisions of this Agreement provided that the communicating or transferring Party determines that such cooperation will promote and will not constitute an unreasonable risk to its defense and security. ARTICLE II Exchange of Information A.EachPartywillcommunicatetoorexchangewiththeotherPartysuchclassified Amended in 1984 to information, sensitive nuclear technology, and controlled nuclear information as is clarify that technology jointly determined to be necessary to: and controlled 1. t he development of defense plans; information will also be 2. t he training of personnel in the employment of and defense against: atomic exchanged. weapons and other military applications of atomic energy; 3. t he evaluation of the capabilities of potential enemies in the employment of atomic weapons and other military applications of atomic energy; 4. t he development of delivery systems compatible with the atomic weapons which they carry; and 5. r esearch, development and design of military reactors to the extent and by such means as may be agreed. B. In addition to the co-operation provided for in paragraph A of this Article each Additional paragraph PartywillexchangewiththeotherPartyotherclassifiedinformationconcerningatomic added in 1984, enlarging weapons, sensitive nuclear technology, and controlled nuclear information, including scope of information special nuclear materials properties and production or processing technology, when, sharing. after consultation with the other Party, the communicating Party determines that the communication of such information is necessary to improve the recipient’s atomic weapon design, development and fabrication capability. ARTICLE III Transfer of Submarine Nuclear Propulsion Plant and Materials A. The Government of the United States may authorize, subject to terms and conditions Paragraph changed in acceptable to the Government of the United States, persons (1) to transfer by sale to the 2014 from the 1958 text Government of the United Kingdom or persons designated by the Government of the allowing sale of a single United Kingdom submarine nuclear propulsion plants and parts thereof, including spare submarine reactor to parts, replacement cores, and fuel elements, as may be agreed by the Parties, and (2) allow sale of multiple to communicate to the Government of the United Kingdom or persons designated by reactors or parts of the Government of the United Kingdom (or to both) information as is necessary for the reactors. design, manufacture, and operation of submarine nuclear propulsion plants. 17 B. The Government of the United States will transfer by sale agreed amounts of U-235 contained in uranium enriched in the isotope U-235 as needed for use in any submarine Amendments in 2014 nuclear propulsion plant transferred pursuant to paragraph A of this Article, on such to allow for transfer of terms and conditions as may be agreed. If the Government of the United Kingdom so uranium 235 for any requests, the Government of the United States will reprocess any material sold under submarine reactors the present paragraph in facilities of the Government of the United States, on terms and transferred from the US. conditions to be agreed, or authorize such reprocessing in private facilities in the United States. Enriched uranium recovered in reprocessing such materials by either Party may be purchased by the Government of the United States under terms and conditions to be agreed. Special nuclear material recovered in reprocessing such materials and not purchased by the Government of the United States may be returned to or retained by the Government of the United Kingdom and any U-235 not purchased by the Government of the United States will be credited to the amounts of U-235 to be transferred by the Government of the United States under this Agreement. C. The Government of the United States shall be compensated for enriched uranium Amendments in 2014 sold by it pursuant to this Article at a price based on the fair market price of comparable to allow for transfer of enriched uranium sold in the U.S. domestic market at the time of the sale. Any purchase multiple submarine of enriched uranium by the Government of the United States pursuant to this Article reactors, including an shall be at the applicable price of the United States Atomic Energy Commission for the updated formula for purchase of enriched uranium in effect at the time of purchase of such enriched uranium. pricing. D.ThePartiesmayexchangeclassifiedinformationonmethodsofreprocessingfuel elements of the type utilized in any propulsion plant transferred under this Article, includingclassifiedinformationonthedesign,constructionandoperationoffacilities for the reprocessing of such fuel elements. E. The Government of the United Kingdom shall indemnify and hold harmless the Government of the United States against any and all liabilities whatsoever (including third-party liability) for any damage or injury occurring after any propulsion plant or parts thereof, including spare parts, replacement cores or fuel elements, transferred under this Article are taken outside of the United States, for any cause arising out of or connected with the design, manufacture, assembly. transfer or utilization of the propulsion plant, spare parts, replacement cores or fuel elements transferred pursuant to paragraph A of this Article. Article III bis, which was added to the treaty ARTICLE III BIS in 1959, contains the operative text for the Transfer of Materials and Equipment transfer of non-nuclear components and nuclear A. The Government of the United States shall transfer to the Government of the United material. Kingdom the following in such quantities, at such times prior to December 31, 2024, and on such terms and conditions as may be agreed: Article III bis sharing has 1. n on-nuclear parts of atomic weapons which parts are for the purpose of improving a sunset clause, initially the United Kingdom’s state of training and operational readiness; December 31 1969, but 2. o ther non-nuclear parts of atomic weapons systems involving Restricted Data repeatedly extended. which parts are for the purpose of improving the United Kingdom’s state Since 1984 extensions of training and operational readiness when in accordance with appropriate have been for ten years requirements of applicable laws; at a time. The last amendment changed all dates in the Article from 2014 to 2024. 18 3. s ource, by-product and special nuclear material, and other material, for research on, development of, or use in atomic weapons when, after consultation with In 1968 the reference the Government of the United Kingdom, the Government of the United States to ‘other material’ was determines that the transfer of such material is necessary to improve the United added, and this text Kingdom’s atomic weapon design, development or fabrication capability. moved to a separate paragraph. ‘Utilization B. The Government of the United States shall transfer to the Government of the United facility’ is a technical Kingdom special nuclear material, and authorize the transfer of other material, for term for a nuclear reactor. research on, development of, production of, or use in utilization facilities for military applications, in such quantities, at such times prior to December 31, 2024, and on such Paragraph added in 1984 terms and conditions as may be agreed. to allow for the transfer of enriched uranium for C. The Government of the United States shall transfer enriched uranium, and shall any purpose, instead of arrange enrichment and other uranium services for the Government of the United just to improve weapon Kingdom, for military purposes, in such quantities, at such times prior to December 31, design or fabrication. 2024, and on such terms and conditions as may be agreed. Text amended in 1994 D. The Government of the United Kingdom shall transfer to the Government of the to allow for the US to United States for military purposes such source, by-product and special nuclear material, arrange enrichment and equipment of such types, in such quantities, at such times prior to December 31, for the UK as well as 2024, and on such terms and conditions as may be agreed. providing it directly. E. 1. W ith respect to by-product material, special nuclear material and other material transferred from one Party to the other under this Article, the recipient Party agrees not to use any such material for purposes other than those for which it was received, provided that material which has lost its identity as a result of commingling with other material of the recipient Party may be put to other uses if the recipient Party retains an equivalent amount of its own material for the purpose for which the other Party’s material was received. 2. F or material or equipment transferred from one Party to the other Party, the recipient Party shall pay or reimburse, as may be agreed, all packaging, transportation and related costs. Packaging, shipping containers and methods of shipment shall be as may be agreed. 3. S hould either Party desire to acquire materials or components for use in the manufacture or in preparation for manufacture of atomic weapons from any source within the jurisdiction of the other Party, the procuring Party shall inform the other Party of the proposed procurement in order that such other Party may determinewhethertheproposedprocurementinvolvesclassifiedinformation and if so whether the proposed procurement is in compliance with its applicable laws and regulations. ARTICLE IV Responsibility for use of Information, Material, Equipment and Devices Theapplicationoruseofanyinformation(includingdesigndrawingsandspecifications), material or equipment communicated, exchanged or transferred under this Agreement shall be the responsibility of the Party receiving it, and the other Party does not provide any indemnity, and does not warrant the accuracy or completeness of such information and does not warrant the suitability or completeness of such information, material or equipment for any particular use or application. 19 ARTICLE V Conditions A. Cooperation under this Agreement will be carried out by each of the Parties in accordance with its applicable laws. Paragraph added in B. Under this Agreement there will be no transfer by either Party of atomic weapons. 1979 to specify that information and material C.ExceptwherespecificallyauthorizedbythisAgreementor,asmaybeagreedforcivil should be used for uses, the recipient Party agrees not to use the information communicated or exchanged, defence plans in mutual or the materials or equipment transferred, by either Party pursuant to this Agreement for interest. Text added other than the preparation or implementation of defense plans, including the evaluation in 2014 to specify the of potential enemy capabilities, in the mutual interests of the two countries inclusion of evaluating enemy capabilities. D. Nothing in this Agreement shall preclude the communication or exchange of classifiedinformation,sensitivenucleartechnology,orcontrollednuclearinformation, Amended in 1984 to which may be transmissible under other arrangements between the Parties. state that sharing of technology and controlled ARTICLE VI information is allowed under other agreements. Guaranties A.Classified information, materials and equipment communicated or transferred pursuant to this Agreement shall be accorded full security protection under applicable security arrangements between the Parties and applicable national legislation and regulations of the Parties. In no case shall either Party maintain security standards for safeguardingclassifiedinformation,materialsorequipmentmadeavailablepursuantto this Agreement less restrictive than those set forth in the applicable security arrangements in effect on the date this Agreement comes into force. B. Sensitive nuclear technology and controlled nuclear information transferred pursuant Additions in 1984 to this Agreement shall be accorded at least the same level of protection by the recipient including protections party as that accorded to such information by the transferring Party. The Parties shall for nuclear technology, consult with each other regarding the appropriate protections for such information. nuclear material and controlled information, C. Adequate physical security shall be maintained with respect to any source material, alongside the original special nuclear material and equipment transferred pursuant to the Agreement, and protection for classified with respect to any special nuclear material used in or produced through the use of information. any material or reactor so transferred. Such protection shall be commensurate with the importance of the material or equipment involved. D.Classified information, sensitive nuclear technology, and controlled nuclear References to controlled information communicated or exchanged pursuant to this Agreement will be made information and nuclear available through channels existing or hereafter agreed for the communication or technology added in exchange of such information between the Parties. 1984. 20 E. Classified information, sensitive nuclear technology, and controlled nuclear information communicated or exchanged, and any materials or equipment transferred, pursuant to this Agreement shall not be communicated, exchanged or transferred by the recipient Party or persons under its jurisdiction to any unauthorized persons, or, except as provided in Article VII of this Agreement, beyond the jurisdiction of that Party. Each Party may stipulate the degree to which any of the information, materials or equipment communicated, exchanged or transferred by it or persons under its jurisdiction pursuant to this Agreement may be disseminated or distributed; may specify the categories of persons who may have access to such information, materials or equipment; and may impose such other restrictions on the dissemination or distribution of such information, materials or equipment as it deems necessary. F. Adequate materials control and accountability shall be maintained with respect to Paragraph on controlling any nuclear material (including source material and special nuclear material) transferred and accounting for pursuant to the Agreement, and with respect to any nuclear material used in or produced nuclear materials added through the use of any nuclear material or equipment transferred pursuant to the in 1994. Agreement. Each Party guarantees adequate materials control and accountancy shall be maintained so long as such nuclear material or equipment remains under its jurisdiction or control. As may be mutually agreed, the Parties shall consult with each other regarding methods and technology for providing such materials control and accountability. ARTICLE VII Dissemination Nothing in this Agreement shall be interpreted or shall operate as a bar or restriction to Minor amendments consultationorcooperationinanyfieldofdefensebyeitherPartywithothernations including reference orinternationalorganizations.NeitherParty,however,shallcommunicateclassified to sharing nuclear information, sensitive nuclear technology, and controlled nuclear information, or transfer technology and or permit access to or use of materials, or equipment, made available by the other Party controlled information pursuant to this Agreement to any nation or international organization unless: added in 1984. A.itisnotifiedbytheotherPartythatallappropriateprovisionsandrequirementsof More detailed conditions such other Party’s applicable laws, including authorization by competent bodies of such on the sharing of other Party, have been complied with as necessary to authorize such other Party directly information with other so to communicate to, transfer to or permit access to or use by such other nation or states and international international organization; and further that such other Party authorizes the recipient organisations added in Party so to communicate to, transfer to or permit access to or use by such other nation 1959. or international organization; or B.inthecaseofcommunicationofclassifiedinformation,sensitive nuclear technology, and controlled nuclear information, and access to materials or equipment, such other Party has informed the recipient Party that such other Party has so communicated such classifiedinformationto,orpermittedaccesstosuchmaterialsorequipmentby,such other nation or international organization; or C. in the case of material which has lost its identity as a result of commingling with other material of the recipient Party, the recipient Party retains an amount under its jurisdiction equivalent to that made available to it by the other Party under this Agreement. 21 ARTICLE VIII Classification Policies Agreed classification policies shall be maintained with respect to all classified information, materials or equipment communicated, exchanged or transferred under this Agreement. The Parties intend to continue the present practice of consultation with each otherontheclassificationofthesematters. ARTICLE XI Definitions For the purposes of this Agreement: A. ‘Atomic weapon’ means any device utilizing atomic energy. exclusive of the means for transporting or propelling the device (where such means is a separable and divisible part of the device). the principal purpose of which is for use as. or for development of. a weapon, a weapon prototype. or a weapon test device. B.‘Classifiedinformation’meansinformation,data,materials,servicesoranyother matter with the security designation of United Kingdom ‘Restricted’ or equivalent Reference to additional orUnitedStatesConfidentialorhigher applied under the legislation or regulations equivalent UK of either the United Kingdom or the United States, including that designated by the classification categories Government of the United States as ‘Restricted Data’ or ‘Formerly Restricted Data’ and added in 2014. that designated by the Government of the United Kingdom as ‘ATOMIC.’ C. ‘Sensitive nuclear technology’ means any information (including information Definitions of sensitive incorporated in a production or utilization facility or important component part thereof) nuclear technology and which is not available to the public and which is important to the design, construction, controlled information fabrication, operation or maintenance of a uranium enrichment or nuclear fuel added in 1984. reprocessing facility or a facility for the production of heavy water, but shall not include information designated as Restricted Data by the Government of the United States.’ D. ‘Controlled nuclear information’ means information protected by the Government of the United States from unauthorized dissemination pursuant to sections 57.b. or 148 of the United States Atomic Energy Act of 1954, as amended. E. ‘Equipment’ means any instrument, apparatus or facility and includes any facility, except an atomic weapon, capable of making use of or producing special nuclear material, and component parts thereof, and includes submarine nuclear propulsion plant, reactor and military reactor. ‘Equipment’ also includes non-nuclear parts of atomic weapons Definition of ‘equipment’ and other non-nuclear parts of atomic weapons systems involving Restricted Data. enlarged to include non-nuclear weapon F. ‘Military reactor’ means a reactor for the propulsion of rival vessels, aircraft or land components in 1959. vehicles and military package power reactors. 22 G. ‘Person’ means:  1. anyindividual,corporation,partnership,firm,association,trust,estate,publicor private institution, group, government agency or government corporation other Agency names removed than the United Kingdom Ministry of Defence and the United States Department in 1979 and replaced of Energy and with government 2. a ny legal successor, representative, agent or agency of the foregoing departments. H. ‘Reactor’ means an apparatus, other than an atomic weapon, in which a self- supportingfissionchainreactionismaintainedandcontrolledbyutilizinguranium, plutonium or thorium, or any combination of uranium, plutonium or thorium. I. ‘Submarine nuclear propulsion plant’ means a propulsion plant and includes the reactor, and such control, primary, auxiliary, steam and electric systems as may be necessary for propulsion of submarines. Paragraph referring to the UKAEA deleted in 1974. J. ‘Non-nuclear parts of atomic weapons’ means parts of atomic weapons which are Definitions of non- specially designed for them and are not in general use in other end products and which nuclear parts and atomic are not made, in whole or in part, of special nuclear material; and ‘other non-nuclear information added in parts of atomic weapons systems involving ‘Restricted Data’ means parts of atomic 1959. weapons systems, other than non-nuclear parts of atomic weapons, which contain or reveal atomic information and which are not made, in whole or in part, of special nuclear material. K. ‘Atomic information’ means information designated ‘Restricted Data’ or’ Formerly Restricted Data’ by the Government of the United States and information designated ‘ATOMIC’ by the Government of the United Kingdom. ARTICLE XII Duration This Agreement shall enter into force on the date on which each Government shall have receivedfromtheotherGovernmentwrittennotificationthatithascompliedwithall Some more complex statutory and constitutional requirements for the entry into force of this Agreement, and wording on terminating shall remain in force until terminated by agreement of both Parties, except that, if not so the agreement was terminated, Article II may be terminated by agreement of both Parties, or by either Party removed in 1984. on one year’s notice to the other to take effect on December 31, 1969, or thereafter on oneyear’snoticetotakeeffectattheendofanysucceedingtermoffiveyears. In 1959 a reference to a 10 year duration was replaced with an initial end date for Article II of 1969. 23 Endnotes 1. ‘US-UK Mutual Defence Agreement’. 9. ‘Amendment to the Agreement between the Government Hansard, 6 November 2014. Vol. 587 Col. of the United Kingdom of Great Britain and Northern 312WH. https://hansard.parliament.uk/ Ireland and the Government of the United States of Commons/2014-11-06/debates/14110640000001/US- America for Cooperation on the Uses of Atomic Energy UKMutualDefenceAgreement. for Mutual Defense Purposes of July 3, 1958’. Her 2. Unless otherwise stated this section is based on Jenifer Majesty’s Stationery Office, 5 December 1979. Cmnd. Mackby and John Simpson. ‘The Special Nuclear 7976. https://treaties.fcdo.gov.uk/data/Library2/pdf/1980- Relationship: A Historical Chronology’. In US-UK Nuclear TS0061.pdf. Cooperation after 50 Years, edited by Jenifer Mackby, and 10. ‘Amendment to the Agreement’, 2014. Op. Cit. Paul Cornish. Washington, DC: Center for Strategic and 11. Rabinder Singh and Christine Chinkin. ‘Peacerights, International Studies, 2008. p5–12. BASIC and the Acronym Institute for Disarmament 3. Richard Moore. ‘British Nuclear Warhead Design Diplomacy: Mutual Defence Agreement and the Nuclear 1958–66: How Much American Help?’ Defence Studies 4, Non-Proliferation Treaty Joint Advice’. Matrix, 20 no. 2 (January 2004): 207–28. https://doi.org/10.1080/1470 July 2004. https://www.nuclearinfo.org/wp-content/ 243042000325913. uploads/2020/09/Mutual-Defence-Agreement-and-the- 4. For example: AWE. ‘Legacy’. https://www.awe.co.uk/ Nuclear-Non-Proliferation-Treaty-Joint-Advice.pdf. about-us/our-history/. 12. ‘US-UK Mutual Defence Agreement’. 5. As of 2014, stocktake meetings were held approximately Hansard, Vol. 587 Col. 313WH, 6 November every 18 months. See: Claire Mills. ‘UK-US Mutual 2014. https://hansard.parliament.uk/ Defence Agreement’. Standard Note. House of Commons, Commons/2014-11-06/debates/14110640000001/US- 20 October 2014. SN/IA/3147. https://researchbriefings. UKMutualDefenceAgreement. files.parliament.uk/documents/SN03147/SN03147.pdf. 13. For a detailed discussion of this increase, see: David 6. ‘Amendment to the Agreement between the Government Cullen. ‘Extreme Circumstances: The UK’s New of the United Kingdom of Great Britain and Northern Nuclear Warhead in Context.’ Nuclear Information Ireland and the Government of the United States of Service, August 2022. p28–30; 34–37. https://www. America for Cooperation on the Uses of Atomic Energy nuclearinfo.org/wp-content/uploads/2022/08/Extreme- for Mutual Defense Purposes’. Her Majesty’s Stationery Circumstances-print-version.pdf. Office, February 1985. Cmnd. 9434. https://treaties.fcdo. 14. Mackby and Simpson, 2008. Op. Cit. p11. gov.uk/data/Library2/pdf/1985-TS0004.pdf. 15. Ibid. p14–15. 7. ‘Amendment to the Agreement between the Government 16. See Cullen, 2022. Op. Cit. p15. of the United Kingdom of Great Britain and Northern 17. ‘Operation DOMINIC I – Fact Sheet’. Defense Threat Ireland and the Government of the United States Reduction Agency, September 2021. https://www. of America for Cooperation on the Uses of Atomic dtra.mil/Portals/125/Documents/NTPR/newDocs/18- Energy for Mutual Defense Purposes’, 22 July 2014. Her DOMINIC%20I%20-%202021.pdf. Majesty’s Stationery Office. Cm 8996. https://treaties. 18. Ian Zabarte. ‘A Message from the Most Bombed Nation fcdo.gov.uk/awweb/awarchive?type=file&item=70116. on Earth’. Al Jazeera. Accessed 11 July 2024. https://www. 8. ‘Amendment to the Agreement between the Government aljazeera.com/opinions/2020/8/29/a-message-from-the- of the United Kingdom of Great Britain and Northern most-bombed-nation-on-earth. Ireland and the Government of the United States of 19. ‘The Republic of Kiribati’s Submission in Accordance America for Cooperation on the Uses of Atomic Energy With Resolution 78/240 Entitled Addressing the for Mutual Defense Purposes’. Her Majesty’s Stationery Legacy of Nuclear Weapons’. Republic of Kiribati, 31 Office, 23 May 1994. Cm 2785. https://treaties.fcdo.gov.uk/ May 2024. https://docs-library.unoda.org/General_ data/Library2/pdf/1995-TS0022.pdf. Assembly_First_Committee_-Seventy-Ninth_session_ (2024)/78-240-Kiribati-EN_0.pdf. 24 20. John Lax and Ceri McDade. ‘Buckets of Sunshine in a 35. Stuart Andrew. ‘USA: Trident Submarines – Question Broken Paradise – the Operation Dominic Nuclear Test for Ministry of Defence – Written Questions, Answers’. Series, 1962, Christmas Island.’ The British Nuclear Test Hansard, 19 October 2018. https://questions-statements. Veterans Association, 25 April 2021. https://www.bntva. parliament.uk/written-questions/detail/2018-10-19/181551. com/buckets-of-sunshine-in-a-broken-paradise-the- 36. See: Claire Mills, 2014. Op. Cit. operation-dominic-nuclear-test-series-1962-christmas- 37. Information taken from: ‘FOI2024/06131’, 2024. Op. island. Cit.; ‘Mutual Defence Agreement’. Hansard Vol. 412, 3 21. See Cullen, 2022. Op. Cit. p12–13. November 2003. ‘Mutual Defence Agreement’. Hansard, 22. Sanem Topal. ‘Nuclear Weapon Modernisation: Attitudes 3 November 2003. https://hansard.parliament.uk/ of Non-Nuclear Weapon States’. Nuclear Information Commons/2003-11-03/debates/10e95018-9e3c-4621- Service, August 2021. https://www.nuclearinfo.org/wp- aa7a-355ef4fbefb2/MutualDefenceAgreement; ‘Nuclear content/uploads/2021/08/Attitudes-to-Nuclear-Weapons- Weapons’. Hansard Vol. 408, 11 July 2003. https://hansard. Modernisation.pdf. parliament.uk/Commons/2003-07-11/debates/6276acf0- 23. ‘Plutonium and Aldermaston – an Historical Account’. 88ab-45b2-b26d-e3d3db28d912/NuclearWeapons; ‘Joint Ministry of Defence, 2000. Working Groups’. Hansard Vol. 304, 12 January 1998. 24. Ibid. https://hansard.parliament.uk/Commons/1998-01-12/ 25. Bob Ainsworth. ‘Trident Missiles: 3 Dec 2009’. Hansard debates/0c7e8f58-693e-414c-aee2-0a6e831128ae/ Column 909W, 3 December 2009. https://publications. JointWorkingGroups; ‘Mutual Defence Agreement’. parliament.uk/pa/cm200910/cmhansrd/cm091203/ Hansard Vol. 289, 27 January 1997. https://hansard. text/91203w0014.htm#09120373000544. parliament.uk/Commons/1997-01-27/debates/095ae56f- 26. ‘Defence Board – Successor Submarine Project – Note e616-49ec-931f-201fcea72681/MutualDefenceAgreement; by the Assistant Secretary’, 25 November 2009. https:// ‘Agreement’. Hansard Vol. 254 Col. 823, 16 February 1995. robedwards.typepad.com/files/declassified-report-to- https://hansard.parliament.uk/Commons/1995-02-16/ mod-defence-board.pdf. debates/ffa95c2f-1d58-430e-b8d0-309823f8dc6a/ 27. Ministry of Defence. ‘FOI2024/04354 – MDA Transfers – Agreement; ‘Joint Working Groups’. Hansard Vol. Response’, 11 April 2024. 378 Col. 1116W, 25 January 2002. https://hansard. 28. Ministry of Defence. ‘FOI2024/06131 – Steve parliament.uk/Commons/2002-01-25/debates/fdaef039- Hucklesby – MDA Joint Working Groups’, 4 June 618c-4383-b4f8-c0975ec9fb35/JointWorkingGroups; 2024. https://www.whatdotheyknow.com/request/ ‘Nuclear Weapons’. Hansard Vol. 488, 27 February 2009. active_joint_working_groups_jowo?nocache=incoming- https://hansard.parliament.uk/commons/2009-02-27/ 2672234#incoming-2672234. debates/09022737000121/NuclearWeapons. The full title 29. Moore, 2004. Op. Cit. of JOWOG 11 is ‘Analysis and specification of materials 30. Ministry of Defence, 2024. Op. Cit. to arrive at common standards’. This figure is based on 31. Ibid. the assumption that JOWOGs are in general active on 32. ‘Reform, Not Renewal – The US-UK Mutual Defence an ongoing basis until their work is no longer deemed Agreement, How It Works and Why It Needs to Be necessary, whereas actual activity may be more complex. Reformed’. Nuclear Information Service, 2014. https:// The numbering of JOWOGs 16-21 can be inferred, but is www.nuclearinfo.org/wp-content/uploads/2022/07/ not certain. The year that some JOWOGs became active Reform-Not-Renewal-Full-Report.pdf. between 1973 and the status of some JOWOGs in 2024 is 33. ‘Nuclear Weapons’. Hansard, 20 January 2011. not certain and is indicated by partial shading in those Column 881W. https://publications.parliament.uk/ years. Some JOWOGs shown as active in 1995 have not pa/cm201011/cmhansrd/cm110120/text/110120w0001. been confirmed as separate groups as data in that year is htm#11012056001705. described as ‘subject areas’. The number of the JOWOG 34. Atomic Weapons Establishment. ‘FOI2024-033 -Final focussing on ‘Weapons Material Management’ and Response’, 18 June 2024. the title of JOWOG 47 cannot be determined from the available data. 25 38. Text compiled by Nuclear Information Service. All effort has been made to ensure accuracy. Sources: ‘Agreement between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the United States of America for Co-Operation on the Uses of Atomic Energy for Mutual Defense Purposes.’ UN, 3 July 1958. Cmnd 537. https:// treaties.fcdo.gov.uk/data/Library2/pdf/1958-TS0041. pdf; ‘Amendment to the Agreement between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the United States of America for Co-Operation on the Uses of Atomic Energy for Mutual Defense Purposes of July 3, 1958’. Her Majesty’s Stationery Office, 7 May 1959. Cmnd. 859. https://treaties.fcdo.gov.uk/data/Library2/ pdf/1980-TS0061.pdf; ‘Amendment to the Agreement between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the United States of America for Co-Operation on the Uses of Atomic Energy for Mutual Defense Purposes of July 3, 1958’. Her Majesty’s Stationery Office, 27 September 1968. Cmnd. 4119. https://treaties. fcdo.gov.uk/awweb/awarchive?type=file&item=66769; ‘Amendment to the Agreement between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the United States of America for Co-Operation on the Uses of Atomic Energy for Mutual Defense Purposes of July 3, 1958’. Her Majesty’s Stationery Office, 22 July 1974. Cmnd. 6017. https://treaties.fcdo.gov.uk/awweb/ awarchive?type=file&item=66769; ‘Amendment to the Agreement’, 1979. Op. Cit.; ‘Amendment to the Agreement’, 1985. Op. Cit.; ‘Amendment to the Agreement’, 1994. Op. Cit.; ‘Amendment to the Agreement’, 2014. Op. Cit. 26 Nuclear Information Service This briefing and a full list of our reports and briefings Reports and briefings are provided free of charge but is available at www.nuclearinfo.org/reports please consider making a donation to support our work. Printed copies can be ordered. 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