Britain secretly sold Israel a key ingredient for its nuclear programme in 1958, according to official documents obtained by BBC News. Papers in the British National Archives show a deal was done to export 20 tonnes of heavy water for about £1.5m. No "peaceful use only" condition was placed on its use. Officials said imposing one would be "over zealous".

http://news.bbc.co.uk/1/hi/uk/4743987.stm

Israel's acquisition of nuclear bombs has been one of the most sustained pieces of deceit in recent history. The project was guarded with such passion that in the 1980s the technician Mordechai Vanunu was kidnapped and spent 11 years in solitary confinement for blowing some of its secrets. It is remarkable then, that documents lying unnoticed in the public records office at Kew should reveal Britain's hitherto unknown role 47 years ago in deceiving the US and supplying Israel with the means to go nuclear. The main files on the subject, from the UK Atomic Energy Authority, are still classified. But BBC Newsnight producer Meirion Jones says he found a handful of key copies in a routinely declassified but obscure Foreign Office counter-proliferation archive. Apart from a passing mention of a British connection in 1998 by Israeli academic Avner Cohen, the UK's key role seems to have been completely unknown to historians. What the documents still fail to reveal, however, is how high up in the Macmillan government the decision was taken to go behind the back of President Eisenhower and load 20 tons of heavy water from Britain on to Israeli ships, thus enabling Israel to start up its Dimona reactor.