Britain secretly sold Israel a key component for its then-fledgling nuclear programme in the late 1950s, not even telling key ally Washington, a report based on British archives said on Wednesday.

Astonishingly, the decision in 1958 to sell 20 tons of heavy water, a vital ingredient for the production of plutonium, appears to have been made by British civil servants with no input from ministers, the BBC report said.

The documents unearthed by BBC television's Newsnight programme, broadcast late on Wednesday (local time), show British officials decided that it would be "over-zealous" to insist Israel use the heavy water only for peaceful purposes.

Previously, the United States had refused to supply heavy water to Israel without such safeguards.

Heavy water is chemically the same as normal water, but where the hydrogen atoms are of the heavy isotope deuterium, in which the nucleus contains a neutron in addition to the proton found normally.

It can be used to turn natural uranium into plutonium, needed for nuclear weapons.

According to Newsnight, the 20 tons of heavy water was part of a consignment which Britain bought from Norway "a pioneer in heavy water production" in 1956, but which was later deemed surplus to requirements.

Although official papers initially presented the sale as a direct deal between Norway and Israel, memos in the National Archives in London reveal that the heavy water was shipped from Britain in Israeli ships in 1959 and 1960.

It was used for the production of plutonium at Israel's top-secret Dimona nuclear reactor in the Negev desert.

The archives appear to show that the decision to sell the heavy water was taken only by civil servants, mainly in the Foreign Office and the UK Atomic Energy Authority, perhaps for economic reasons.

Newsnight said it had found no evidence that ministers in the then-British government of Prime Minister Harold Macmillan were ever consulted about the sale, or even told about it.

After a British newspaper exposed the Israelis' work at Dimona in 1960, Britain refused a second Israeli request for more heavy water.

The records show an explicit decision not to inform the United States, the report said.

"On the whole I would prefer NOT to mention this to the Americans," concluded a document written by Donald Cape, a Foreign Office official.

Robert McNamara, who served as President John F. Kennedy's defence secretary from 1961, shortly after the sale, told Newsnight he was "astonished" at the revelation.

(China Daily August 5, 2005)