When German-born Scientist Klaus Fuchs was sent to prison in 1950 for slipping British atomic secrets to the Russians, many of his toughest mathematical chores were taken over by chubby Boris Davison, a top scientist at Harwell. Dr. Davison got a complete security clearance, though he was born in Russia (to a British father and a Russian mother) and his mother still lives in the Soviet Union. When another top atomic scientist, Italian-born Bruno Pontecoryo, absconded to Russia with nobody-knows-how-much secret information, Dr. Davison got another checkup, and was cleared, even though it was known that he still wrote regularly to his mother in Russia. He voluntarily submitted all letters to and from his mother to British security officers.
Last week, after the Cabinet had discussed his case, the British government revoked Davison's security clearance and decided to send him to Birmingham University to do nonsecret work. There was no allegation of any disloyal act by Davison himself: his integrity was not questioned. Nonetheless, the government had decided that since he has relatives in Russia, he might be subject to blackmail by threats to their safety. The British now accept what the U.S. has long believed: that a man can be a security risk without being disloyal.
As Davison packed his bags, investigators began to "P.V." (for "Positively Vet") 14,000 scientists and clerks in Britain's atom project. The British recognize that American misgivings about British security measures are one reason why the U.S. refuses to trade atomic information with its closest ally.