Collaboration between US and UK scientists helped develop the Trident nuclear missiles. Credit: TRH

The impending renewal of a pact on nuclear research between the United Kingdom and the United States could breach the Nuclear Non-Proliferation Treaty (NPT), British lawyers say.

Critics argue that the two countries have long been in violation of the NPT, the cornerstone of international attempts to halt the spread of nuclear arms, both in spirit and in the letter of the law. But this year's pending renewal of the US/UK Mutual Defence Agreement (MDA) prompted advocacy groups to seek a legal opinion on the matter. Armed with this advice, they are hoping to force both countries to take disarmament more seriously.

The MDA dates from 1958 and allows for the exchange of plans for the research and development of nuclear weapons between Britain and the United States. Such collaboration aided the development of Britain's nuclear weapon system, Trident, for example. But both countries have also signed the NPT, which came into force in 1970 and requires them to work towards disarmament.

Britain and the United States have improved their weapons systems since the NPT became binding, arguing that they have stuck to its spirit by working to reduce the overall number of nuclear arms. Disarmament advocates counter that any work to improve weapons is a legal breach of the treaty.

It is a grey area, but lawyers have now tipped the balance in favour of those who criticize the MDA. “It is strongly arguable that the renewal of the MDA is in breach of the NPT,” conclude Rabinger Singh and Christine Chinkin, lawyers at Matrix Chambers in London, who were hired by a number of UK-based advocacy groups.

Neither Britain nor the United States will discuss details of the research that goes on under the agreement. A spokesman for the UK Ministry of Defence points out that the allies regularly exchange information on how to safeguard existing nuclear weapons, rather than information about developing new ones. But researchers who took part in previous MDA collaborations, including Bob Peurifoy, former chief weapons designer at Sandia National Laboratories in Albuquerque, New Mexico, say that weapons development has definitely been part of discussions in the past. “The designs were better because of the exchange,” Peurifoy says.

Britain has already declared its intention to renew the MDA for a further 10 years, and the agreement is expected to pass through US Congress without debate.

The British American Security Information Council, one of the advocacy groups that commissioned the Matrix lawyers, says that it is considering seeking a judicial review of the UK decision to renew the MDA—if it can come up with the money needed to do so.

Daryl Kimball, executive director of the Arms Control Association in Washington DC, says the lawyers' conclusion highlights the secrecy that surrounds the MDA. “The United States and the United Kingdom should be more transparent. If no there is no violation, they should provide more information,” he says.