Britain's H-bomb triumph a hoax: Patriotic scientists created an elaborate and highly secret bluff to disguise dud weapons, Peter Pringle reports from New York

LAST week the United States announced it was extending its moratorium on nuclear testing - including the testing of British nuclear weapons in the Nevada desert - for another year, until September 1995. That is after the non-proliferation treaty is due for renewal, in May 1995, and could mean the end of British nuclear tests for good.

If so, it will be the final chapter in a story that goes back to an elaborate bluff in the late 1950s over the nation's early H-bombs. Declassified documents from the Public Records Office reveal scientists claimed they had sucessfully tested three bombs when, in fact, two were duds. The third made a big bang but it was not an H-bomb.

For almost four decades, 'Short Granite', 'Purple Granite' and 'Orange Herald' have been the official codenames of British H-bombs tested in the Pacific in 1957. Reported by newspapers of the day as evidence of Britain's triumphant entry into the elite club of H-bomb nations, which then only included the United States and the Soviet Union, the two 'Granite' tests were of H-bomb design but they fizzled, and 'Orange Herald' was a massive A-bomb.

The bluff was so successful that even defence chiefs not directly involved were kept in the dark, and the then prime minister, Harold Macmillan, was also misled.

The two 'Granite' bombs used hydrogen isotopes instead of the uranium and plutonium fuel used in the older A-bombs, but the devices were duds, according to an obscure report by the National Radiation Protection Board based on the newly declassified figures. The Aldermaston bluff is also confirmed by the authors of a new US book on British nuclear weapons history, published this week in Washington.

A handful of academics in Britain and the US, including Professor Norman Dombey of the University of Sussex and his co-author, Eric Grove, formerly of the Royal Naval College, have suspected the bluff for some time. They thought all three bombs might have been H-bomb attempts using a formula adopted earlier by the Russians - who also failed to produce a big bang first time around.

Now the record confirms their suspicions but shows the formula for the 'Granite' bombs was the same as that used by the Americans, the so-called two-stage H-bomb invented and successfully tested by Edward Teller and Adam Ulam. The explosive yield expected from the Teller-Ulam design was at least in the megaton range - the equivalent of 1 million tons of TNT, more than 70 times bigger than the bomb that destroyed Hiroshima. The two 'Granite' bombs produced less than one third of a megaton.

One of several remarkable aspects of the hoax is that it was carried out as an act of supreme patriotism by probably no more than a dozen scientists led by Sir William Penney, the director of the nuclear weapons factory at Aldermaston. In 1954, Churchill had ordered him to make a bomb in the megaton range for use in the Blue Steel and Blue Streak missiles, which were later cancelled. As work on the bombs proceeded, public protest over fallout from the US bomb tests was growing and the scientists at Aldermaston knew their time for aerial tests was short.

In the 1957 tests, which took place on the Malden Islands in May, Sir William Penney was concerned that the two-stage H-bomb design in the 'Granite' bombs had been so hurriedly put together that they would not work, so he inserted 'Orange Herald', the older, proven uranium bomb as a 'fall-back', and that is the one British journalists watched being detonated and wrote up as though it was an H-bomb.

The new documents show that Britain's first real H-bomb, codenamed Grapple X, was not detonated until November the same year on Christmas Island. The yield of Grapple X was 1.8 megatons, far bigger than even the Aldermaston scientists had predicted.

The new US book is volume five in a series called the Nuclear Weapons Databook produced by researchers at the Natural Resources Defence Council, a group of highly respected enviromental researchers in Washington. One of the authors, Stan Norris, says the British bluff did not altogether surprise him. 'It was a period when nuclear weapons symbolised global power; nations sacrificed a lot to become a member of the club,' he says.

What has surprised Dombey and Grove is that the scientists were able to extend their hoax into the uppermost reaches of the British defence establishment.

And what has surpised all the researchers is the extent of the help given to Aldermaston by the Americans. The extraordinary story puts more dents in the already battered idea of Britain's nuclear deterrent being 'independent'.

In 1958, after Britain with its relatively meagre resources at Aldermaston had proved it could build an H-bomb on its own, President Eisenhower successfully urged the US Congress to amend the Atomic Energy Act so that the free flow of nuclear weapons information that existed during the war but which was halted immediately the war was over, could be resumed.

From previously classified documents of the US Atomic Energy Commission, Norris and his co-authors discovered that the US simply handed over blueprints of nuclear warheads and these then went into production at Aldermaston, under US supervision. Within three years of the 1958 amendment to the US Atomic Energy Act, American scientists had handed to Britain 16 blueprints for nuclear weapons designs. The number of blueprints handed over since then is not known, but the flow continued into the Reagan administration.

(Photographs omitted)