The United Kingdom
was the third country to test an independently developed nuclear weapon
, in October 1952. It is one of the five "Nuclear Weapons States
" (NWS) under the Nuclear Non-Proliferation Treaty
, which the UK ratified in 1968. The UK is currently thought to retain a weapons stockpile of around 160 operational nuclear warheads
and 225 nuclear warheads in total.
Since the 1958 US-UK Mutual Defence Agreement
, the United States
and the United Kingdom have cooperated extensively on nuclear security matters. The special relationship
between the two countries has involved the exchange of classified scientific information and nuclear materials such as plutonium
. The UK has not run an independent nuclear weapons delivery system development and production programme since the cancellation of the Blue Streak missile
in the 1960s, instead it has pursued joint development (for its own use) of US delivery systems, designed and manufactured by Lockheed Martin
, and fitting them with warheads designed and manufactured by the UK's Atomic Weapons Research Establishment and its successor the Atomic Weapons Establishment
. In 1974 a US proliferation assessment noted that "In many cases is based on technology received from the US and could not legitimately be passed on without US permission."
In contrast with the other permanent members of the United Nations Security Council
, the United Kingdom currently... Read More