How Cambridge spy No5 beat the courts

THE fifth Cambridge spy was spared prosecution because his brother was the government’s chief economic adviser, the files reveal.

John Cairncross is believed to have passed atomic secrets to his Russian handlers during the Cold War.

But officials feared they did not have enough evidence to prosecute and also that damaging headlines would embarrass his brother Alec.

In a note to prime minister Sir Alec Douglas-Home, cabinet secretary Burke Trend wrote: ‘Apart from the distress and embarrassment this would inflict on an individual whose integrity we have no reason to question, we have to ask ourselves what would be the probable result… if it became known the government were employing, as their chief economic adviser, a man who is the brother of a selfconfessed Communist spy.’

John Cairncross was one of the notorious Cambridge spies recruited by Soviet intelligence while at university in the 1930s. He was the last of the group to be identified. The others were Kim Philby, Donald Maclean, Guy Burgess and Anthony Blunt.

Cairncross later held a series of sensitive government posts, including working at the Bletchley Park codebreaking centre, and is thought to have been the first to alert the Soviets to Britain’s plans to develop an atomic bomb.