MI5’s leading supporters in the 20th century were Britain’s two most successful prime ministers: Winston Churchill and Clement Attlee. Churchill, who had been one of its founders in 1909, was full of praise for its top secret contribution to victory in the Second World War. But he had less personal contact with MI5 than Attlee, and it is often forgotten that, at his own request, Attlee saw the Director-General far more frequently than any other 20th-century prime minister.
The most dramatic moments in MI5’s peacetime contact with Number 10 derived from three attempts to assassinate British prime ministers. Two – those against Margaret Thatcher and John Major – came close to success.
However, until 1989, all British prime ministers, both Conservative and Labour, did their best to prevent any public or parliamentary discussion of both MI5 and MI6. Harold Wilson shared Harold Macmillan's conviction that ‘It is dangerous and bad for our general national interest to discuss these matters’. Both would have been strongly opposed to the current exhibition at The National Archives.
Christopher Andrew is Emeritus Professor of Modern and Contemporary History at the University of Cambridge and former visiting professor at Harvard, Toronto and the Australian National University. He is a former MI5 officer, its first official historian, and author of the first history based on its secret archives. His latest book, The Spy Who Came in from the Circus, contains further revelations on the history of both MI5 and MI6.
Discover the full season of events accompanying our free exhibition, MI5: Official Secrets open from 5 April to 28 September.