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As the author of iconic verse from Funeral Blues to Night Mail, Wystan Hugh Auden is one of Britain's most popular poets.

Less well known is his unlikely role as a suspect in one of the most high-profile Cold War defections by a Soviet spy.

Secret documents released today show how the author - loved and loathed during his lifetime by the literary and political Establishment - was closely questioned over the disappearance of Guy Burgess, the famously dissolute member of the Cambridge Five spy ring which passed key secrets to the Soviet Union.

MI5 and the American FBI ordered the interrogation of the poet when it emerged that Burgess, who fled Britain in May 1951 with fellow diplomat and double-agent Donald Maclean, had urgently tried to phone Auden the night before the defection.

Maclean, who had extensive knowledge of Anglo-American atom bomb research, and the flamboyantly gay Burgess boarded a ferry to France on 25 May before being flown secretly to Moscow.

They had been tipped off by fellow Cambridge spy, Kim Philby, who was working for MI6 in Washington, that they were about to be unmasked.

The disappearance of the two men led to a panic in the British government and security services, sparking a Europe-wide manhunt in which WH Auden became one of those suspected of assisting Burgess, possibly by sheltering him in his Italian holiday home.

The documents, published at the National Archives in Kew, west London, show how MI5 officers suspected Auden was "deliberately prevaricating" when he claimed he could not remember being told about Burgess's phone call.

Following consultation with the FBI, MI5 ordered that his cottage on the island of Ischia in the Bay of Naples be watched by the Italian security services and declared him a "candidate for interrogation".

Their suspicions were increased when Auden arrived at his villa three days after Burgess's disappearance.

The poet may have had good reason to want to avoid the British authorities.

He was accused of cowardice and betrayal when he emigrated to America shortly before the outbreak of the Second World War with his literary collaborator and sometime lover Christopher Isherwood.

Auden, who also made no secret of his homosexuality among his circle of friends, had known Burgess since the 1930s and the pair met frequently after the diplomat was posted to the British embassy in Washington DC in 1947.

The MI5 file reveals that Auden, who saw the 100th anniversary of his birth celebrated this month with renewed debate about the literary merits of his work, was also considered by the Security Service to be one of a clique of British "intellectual Communists", albeit with little or political influence.

One MI5 memo from 1938 stated: "WH Auden was described in a letter to [MI6] concerning [poet and some-time Communist] Cecil Day Lewis as an intellectual Communist of a highly idealistic and literary brand.

Harry Pollitt [head of the Communist Party of Great Britain] was stated to think less than nothing of his value to the Party."The secret file shows that in the hours after Burgess's disappearance, MI5 was told that the night before the defecting spy had phoned the north London home of another leading British poet, Stephen Spender, where Auden was staying.

Burgess, who was renowned as a heavy drinker and had been sent back to London in disgrace from his Washington posting, was "most anxious" to speak to Auden and had also called on 20 May, according to the documents.

The file states that Spender told police he had passed the message on to Auden.

But Auden in turn denied any knowledge of being told about the phone calls - raising the suspicion of the Security Service that he was somehow involved in Burgess's disappearance.

Using an unnamed contact, MI5 officers arranged for Oxford-educated Auden to be interviewed about his relationship with Burgess.

The file stated: "Our object is to get a detailed chronological account of Auden's association with Burgess, a list of their mutual friends and, of course, Auden's views on whether any aspect of their association could have, in retrospect, seem[ed] significant to his disappearance."

It then added cryptically: "The value of the interview may well lie as much in what Auden fails to say as in what he volunteers."

Although Burgess was considered to have been less important to the Kremlin than Philby and Maclean, his disappearance was the first warning that Britain's security services had been penetrated by a Soviet spy ring.

Thousands of documents were transferred into Soviet hands by the men and it is likely Burgess was ordered to accompany Maclean to Moscow because it was feared his indiscretion would lead to the unmasking of Philby, who continued to operate for a further decade.

The Auden file casts light on the paranoia in the Security Service about the left-wing sympathies of leading figures in the art and literary worlds at the height of the Cold War.

As well as Day Lewis, Spender and Isherwood, the files mention links between Auden and Aldous Huxley and the French author and statesman Andre Malraux, who arranged for the poet to be smuggled into Spain during the civil war.

It also mentions that Auden was a suspected member of a "group of persons involved in sexual perversion" including his German wife Erika Mann, the daughter of the author Thomas Mann.

Auden married Mann, who was also gay, in 1935 to allow her to escape the Nazi regime.

Although Auden avoided the MI5 interrogation by travelling straight from Italy back to his adopted country of America, the file records that the poet later changed his story to an unnamed informant about not being told of Burgess' calls.

A memo from MI5 to MI6 said: "Auden reluctantly admitted that Spender was probably right in saying he had told Auden of Burgess's telephone calls. Auden had been drinking heavily. [Unnamed source] felt it likely that Auden was lying when he previously stated he remembered nothing of Burgess's calls."

Despite carefully recording all visits to the poet's holiday cottage throughout the summer, MI5 in the end decided it was "impossible to substantiate" a link between Burgess's escape and Auden.

For his part, the poet shrugged off the incident, saying it was likely that if Burgess had been trying to get in touch with him it would only have been to finalise a visit to Italy the two man had discussed some months earlier.

The file said: "Auden surmises that if Burgess did in fact telephone him he was probably trying to complete plans for his holiday."