Wartime MI5 chief was on side of Nazis

Overheard, the RAF and the Luftwaffe were struggling for mastery of the skies. Britain, after the "miracle" of Dunkirk, was fighting for its life.

Overheard, the RAF and the Luftwaffe were struggling for mastery of the skies. Britain, after the "miracle" of Dunkirk, was fighting for its life.

But the conflict was not confined to the armed forces. Britain's premier security service, MI5, was hard at work protecting the citizenry from Nazi subversion. Or was it?

According to an extraordinary report, released after 60 years in Whitehall's secret archives, MI5 in the opening phase of the war was a shambles. Its director, after 31 years in the job, had no idea what was going on. His successor was little better. Most astonishing, the deputy director, William Crocker, was a Nazi sympathiser opposed to the war with Hitler.

Had Neville Chamberlain remained at Downing Street, it is possible that nothing would have changed. As it was, Churchill, newly installed as Prime Minister, realised immediately that something was wrong and called in Sir David Petrie, a colonial intelligence specialist, to stop the rot.

Petrie's report was devastating. MI5, he said, was obsessed with Communism, anti-Labour and under the influence of people opposed to the very concept of war with Germany.

The content of Petrie's report has been the source of speculation by historians for years. Although not scheduled for release until 2020, it was apparently released under the early review system several weeks ago.

Petrie concluded that MI5 staff were "dispirited from a variety of causes, including breakdown, lack of direction, pressure of work, disorganisation, complaints of delay and alleged interference from outside". Petrie reserves his strongest criticism for Crocker, who was appointed by a Home Department committee. "The introduction under outside authority of an entirely new deputy director was an unfortunate mistake," he wrote. "The evil that this man did lives after him."

Petrie does not name the evil-doer, but it was Crocker, a solicitor who had been joint head of B Branch (Investigations), alongside the top spy-hunter Guy Liddell.

Before the war, Crocker had built up a reputation for tracking down insurance fraudsters, and his key role at MI5, under Defence Regulation 18B, was to round up fascist sympathisers reckoned to be a danger to the state. What his bosses did not realise was that he was at the same time active in Truth, a journal openly supportive of Sir Oswald Mosley, jailed leader of the British Union of Fascists, whose followers were often the subject of his internment orders.

Crocker nearly precipitated the resignation of more competent colleagues, including Liddell, in August 1940. Only the "critical war situation" convinced them to stay. Crocker himself left in September 1940.

"This is a very important document which shows just what a mess MI5 was in at the beginning of the war," said David Turner, the historian who found the report at the Public Records Office. "It tells us much we did not know." The MI5 in-house history glossed over those events, he said.

Despite a massive increase in staff, MI5 coped badly during the period after the outbreak of war in 1939 and the founding director, Sir Vernon Kell, was sacked by Churchill. But matters still did not improve and Petrie was called in.

Petrie is deeply critical of Kell's successor Brigadier "Jasper" Harker. "The complaint from all quarters... has been clear and insistent against lack of direction and weakness of control."

He notes that pre-war MI5 recruitment was done through the Old Boy Network - mainly friends and acquaintances. Vetting of recruits was handled at a low level, which might explain the ease with which - in spite of a prevailing anti-Communist mood - the Cambridge spy ring, controlled by the Soviet mole Anthony Blunt, was welcomed into the fold.

Petrie recommended wholesale reform and, at Churchill's insistence, agreed to become director general. Under him MI5 scored notable successes in the war. But Crocker was no less successful. He was knighted and became president of the Law Society.