Extension of US-UK nuclear co-operation arrangements will support Trident replacement

Britain is stepping up co-operation with the USA over its Trident nuclear weapons programme under the terms of a controversial agreement between the two nations which allows the sharing of nuclear technology.

The US-UK Mutual Defence Agreement (MDA), one of the most important agreements underpinning the military “special relationship” between the US and the UK, is to be extended for a further ten years spanning a critical period in the programme for replacing the UK's Trident nuclear weapons programme.  Existing arrangements for co-operation on the design of nuclear warheads will be extended to allow closer collaboration on design of nuclear reactors to power the new submarines which will carry the UK's Trident ballistic missiles, and the two countries will also increase intelligence and information-sharing aimed at preventing the spread of nuclear weapons technology.

The MDA was first signed in 1958 and under current arrangements its terms are reviewed and the Agreement is renewed by the US and UK governments every ten years.  However, critics argue that the MDA undermines global non-proliferation efforts and demonstrates that the UK's nuclear weapons are dependent upon American technology.

19 MPs have signed an Early Day Motion expressing concerns about renewal of the Agreement, and Labour MP Jeremy Corbyn has asked the House of Commons Backbench Business Committee to consider allocating time for a debate on renewal of the MDA.  If granted, this will be the first time that Parliament has debated the Agreement for twenty years.

Previous governments have made it clear that debate on the issues involved would not be welcome.  "A debate on the renewal of the MDA would be used by some as an opportunity to raise wider questions concerning the possible renewal of the nuclear deterrent…and our obligations under the nuclear non-proliferation treaty," notes an internal MoD briefing to the Labour government's defence ministers at the time the MDA was last renewed in 2004.  The paper was released following a freedom of information act request made by Nuclear Information Service.

The latest ten-year amendment to the MDA was laid before Parliament on 16 October as a 'paper subject to negative resolution', meaning that there is a presumption it will be adopted unless Parliament votes otherwise.  Similar papers were laid before the US Congress by President Obama in July, and the necessary ratification period in the USA has now passed without any objection to renewal of the Agreement.

Proposed revisions to the Agreement are significant, and would allow an expansion of the nuclear relationship between the UK and the USA.

The modified Agreement would extend co-operation between the two nations on reactor technology for nuclear-powered submarines.  When the MDA was first signed in 1958, the USA agreed to provide the UK with a single nuclear submarine propulsion plant  to kick-start the Royal Navy's programme to develop nuclear submarines.  For many years afterwards the US Navy maintained a strict embargo on further co-operation on reactor design, with the aim of preventing the British becoming dependent upon American technology, but recently dialogue in this field has recommenced.  

Although played down by the government as an “update” to the MDA, the proposed new arrangements will allow the US to transfer nuclear propulsion plants and components to the UK – including replacement reactor cores, fuel elements, and spare parts – and also pass on information necessary for the design, manufacture, and operation of submarine nuclear propulsion plants.  

The government announced in 2011 that the new 'Successor' class ballistic missile submarines which will replace the Royal Navy's current 'Vanguard' class Trident submarines will be powered by US-designed third generation pressurised water reactors (PWR3).  The USA has had a strong hand in design of the Successor PWR3, with ongoing technical exchanges on the latest US submarine reactor design taking place between the Royal Navy and the US Navy, government officials, and shipbuilders, contractors, and suppliers involved in submarine construction on both sides of the Atlantic.  A British-based office comprised of around 40 US personnel provides full-time engineering support for the exchanges.

The new changes to the MDA open the possibility that reactor components will be purchased from the USA, and in the longer term that US contractors may begin to play a role in the operation and maintenance of the Royal Navy's nuclear propulsion programme.

The extended Agreement will also allow the transfer of special nuclear materials and non-nuclear warhead components between the two nations, although details of these transfers remain confidential.  Existing arrangements which allow the exchange of information on nuclear warhead design remain unchanged.

Changes to the broad scope of the Agreement would enable the two countries to increase co-operation on nuclear counter-proliferation, aimed at preventing the spread of nuclear weapons technology.  A modification to the MDA's introduction reaffirms that “the spread of atomic weapons technology, potentially including State and sub-State actors, imperils the defense and security of both nations".  The modified Agreement confirms that ongoing nuclear Threat Reduction activities between the US and the UK include “evaluation of potential enemies, whether state or non-state actors”, providing a framework for the exchange of information and intelligence on nuclear proliferation and security risks.  Further changes, aimed at extending the role of the Agreement in military planning to include “the evaluation of potential enemy capabilities” also boost the scope for nuclear intelligence exchanges between the two countries.

Although the government has published the text of the amendments to the MDA itself, it has refused to release the classified appendices to the Agreement “because of the sensitivity of their contents”.

However, an explanatory memorandum to MPs prepared by the Foreign and Commonwealth Office states that co-operation with the USA under the MDA has been of “considerable mutual benefit” and has allowed the UK to “significantly reduce costs” of its nuclear weapons programme.  The memorandum acknowledges “a level of procurement dependence on the US” for the nuclear weapons programme but claims that the UK could manufacture an entirely indigenous capability “but chooses not to for economic reasons”.

The memorandum asserts that procurement under the MDA of non-nuclear components of nuclear  weapons is “in full compliance with our obligations under the Nuclear Non-Proliferation Treaty” (NPT), but avoids the controversial issues of whether the transfer of nuclear know-how and materials are compliant with the NPT, and whether extension of the MDA is consistent with the international obligation on the nuclear-armed states to pursue nuclear disarmament measures in good faith.

The government claims that “none of the proposed changes seek to pre-empt a Main Gate acquisition decision on the successor to the Vanguard submarine in 2016”.  However, ratification of the amended MDA will represent a significant milestone in delivery of the Trident replacement programme.

Both the UK and US governments argue that continued co-operation on nuclear weapons technology is in the national interests of both nations.  In a message to Congress urging adoption of the amendments to the MDA, President Obama wrote that, based on previous close cooperation “and the fact that the United Kingdom continues to commit its nuclear forces to the North Atlantic Treaty Organization”, it is “in the United States national interest to continue to assist the United Kingdom in maintaining a credible nuclear deterrent”.


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