Wartime MI5 agent who spied on Nazi sympathisers was bank clerk

Files released by the National Archives in Kew, west London, suggest the agent who posed as an undercover Gestapo officer was actually Eric Roberts, a father of two in his thirties who had been living quietly near Epsom racecourse in Surrey.

The disclosure comes after documents released earlier this year revealed how the agent - operating under the alias Jack King - had been able effectively to control the activities of hundreds of “Fifth Columnists”, neutralising the threat to Britain’s war effort.

The release sparked a flurry of speculation as to King’s real identity, but Professor Christopher Andrew, the author of the official history of MI5, said it was now clear from the files that it was Roberts. From the brief details about him contained in the files, he seems an unlikely candidate for such clandestine - and potentially dangerous - work.

Even his colleagues working at the Euston Road branch of the Westminster Bank in Hampstead, north London, were taken aback when, in 1940, he was suddenly plucked by MI5 from obscurity for special wartime work of “national importance”.

The bank’s assistant controller, RW Jones, wrote to MI5, seeking an explanation.

“What we would like to know is what are the qualifications of Mr Roberts - which we have not been able to perceive - for some particular work of national military importance which would take him away from his normal military call-up in October?”

According to his personal record sheet, his qualifications for performing the role of an undercover Gestapo officer appear thin as he had only a “slight” knowledge of German, although he had twice visited the country on holidays in the 1930s.

He had, however, somehow acquired a knowledge of the pro-Nazi groups operating in Britain in the period before the outbreak of the Second World War.