The incident took place in 1958 when the UK detonated Grapple Y over Christmas Island in the Pacific Ocean. Veterans say they were left with cancer and infertility problems. In the new book, Between Heaven and Hell, journalist Alan Rimmer cites documents released under Freedom of Information laws which state the massive bomb created rain-producing thunder clouds.
The Government and the Ministry of Defence have always denied reports that it rained following the Grapple Y blast.
Ken McGinley, 74, a Royal Engineer from Johnstone, who has battled for compensation for 30 years, said: "This is evidence we were used as guinea pigs. The 50-year cover-up is exposed."