The Los Alamos National Laboratory is preparing an underground sub-critical nuclear test for the Nevada USA test site called 'Vito' at noon today local time.

Apparently the UK will be participating in this test under the 1958 Mutual Defence Agreement and data from the test will be fed into a supercomputer at the UK Atomic Weapons Establishment in Aldermaston.

Defence Minister Dr Lewis Moonie answered a Parliamentary Question to this effect on Tuesday which the MoD says serves as their official statement.

While not strictly in breach of the provisions of the Comprehensive Test Ban Treaty which the UK has ratified and fully supports in principle, it certainly is contrary to the spirit of the CTBT which was originally envisaged to be a step towards nuclear arms control and a means of curbing proliferation.

While being told that the test is for "reliability and predictability" of existing stockpiles of nuclear warheads, such data can be used to modify and enhance nuclear warhead design. We believe that this test could be used to design a replacement for existing Trident warheads, clearly a breach of the UK obligations under the Non-Proliferation Treaty.

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Press Officer Nigel Chamberlain 07968 420859