<P> The UK government signed the Partial Test Ban Treaty on 5 August 1963 along with the United States and the Soviet Union which effectively restricted it to underground nuclear tests by outlawing testing in the atmosphere, underwater, or in outer space . The UK signed the Comprehensive Test Ban Treaty on 24 September 1996 and ratified it on 6 April 1998, having passed the necessary legislation on 18 March 1998 as the Nuclear Explosions (Prohibition and Inspections) Act 1998 . </P> <P> A series summary of British testing is shown here: United Kingdom's nuclear testing series . Note that the Vixen safety tests are not usually listed along with the "real" nuclear testing in lists of British tests . However, they are included in totals for US, USSR, Chinese and French testing . Their outcomes are not known, though they are for most other safety tests . </P> <P> The UK has relied on the Ballistic Missile Early Warning System (BMEWS) and, in later years, Defense Support Program (DSP) satellites for warning of a nuclear attack . Both of these systems are owned and controlled by the United States, although the UK has joint control over UK - based systems . One of the four component radars for the BMEWS is based at RAF Fylingdales in North Yorkshire . </P> <P> In 2003 the UK government stated that it will consent to a request from the US to upgrade the radar at Fylingdales for use in the US National Missile Defense system . </P>

Where are the uk's nuclear weapons stored