MI5 was baffled to discover there were no records of Charlie Chaplin's birth when it investigated his alleged communist sympathies, newly released files reveal.
British intelligence officers could find no documents confirming the silent film star was born in London in April 1889, and they dismissed claims that he was in fact originally from France.
The mystery of Chaplin's birth emerged when the US authorities asked MI5 to look into the comic actor's background after he left America in 1952 under a cloud of suspicion over his communist links.
The star is believed to have been born on April 16 1889 in East Street, Walworth, south London - just four days before the birth of Adolf Hitler, whom he lampooned in his classic 1940 film The Great Dictator.
But after scouring the files at Somerset House in London for his birth certificate, including checks for his supposed alias "Israel Thornstein", MI5 concluded: "It would seem that Chaplin was either not born in this country or that his name at birth was other than those mentioned."
Scotland Yard's Special Branch added to the intrigue by passing on a tip from a source who claimed the actor was born near Fontainebleau, just south of Paris.
A police memo to MI5 noted: "There may or may not be some truth in this, but in view of the fact that no documentary proof has been obtained that Chaplin was born in the United Kingdom, it may well be that he was in fact born in France."
MI6, Britain's foreign intelligence service, investigated further but found no trace of Chaplin's birth in either Fontainebleau or nearby Melun.
However, John Marriott, then head of MI5's counter-subversion branch, was not convinced that the absence of a birth certificate was a matter of concern for the intelligence services.
He wrote: "It is curious that we can find no record of Chaplin's birth, but I scarcely think that this is of any security significance."
Having escaped grinding poverty to launch a career in British music-hall, Chaplin moved to the US in 1910 and made a series of hugely successful films in Hollywood in his famous persona of the "Little Tramp".
But in the early 1950s, when Washington was in the grip of McCarthyist paranoia about Soviet infiltration, he was reviled in the US as a communist sympathiser.
There was further controversy about his two marriages to 16-year-old girls, failure to take American citizenship, and claims he fathered an illegitimate child and owed 2 million dollars in back taxes.
Chaplin and his family sailed to Britain in September 1952 to attend the premiere of his new film Limelight.
While they were out of the country, US attorney-general James McGranery announced he would deny the actor a re-entry permit because of his alleged Soviet connections.
Chaplin's previously secret MI5 files, released by the National Archives in Kew, west London, show that security officials were concerned about whether to steer British VIPs away from meeting the comic.
A telegram sent to MI5's liaison officer in Washington in October 1952 pleaded: "We have very little information on which to guide any highly placed persons likely (to) encounter Chaplin during his visit here. Can you help?"
The reply, which was copied to MI5 director general Sir Percy Sillitoe, noted tersely: "Chaplin has given funds to communist front organisations. Understand US government cannot prove party membership.
"He has been involved in paternity and abortion cases. Being an alien, Immigration can exclude him for moral turpitude."
John Cimperman, the FBI's legal attache at the US Embassy in London, wrote to MI5 on October 20 1952 with a detailed request for information about Chaplin's background.
He asked whether British intelligence had any record of a pre-1947 article in the Soviet newspaper Pravda which apparently contained an "enthusiastic tribute" to "comrade Charlie".
Cimperman also requested any information which would confirm that Chaplin either belonged to the Communist Party or was regarded as "the equivalent of a Party member".
In addition, he inquired whether MI5 was aware of the actor making "financial and/or cultural contributions" to the communist movement, or ever travelling to the Soviet Union.
MI5 officers carried out investigations but were unable to confirm any of the Americans' suspicions.
And a note sent to the intelligence agency's East Africa liaison officer ahead of a safari holiday Chaplin took in Kenya in February-March 1958 shows that MI5 was unimpressed by Washington's claims of communist links.
It stated: "We have no substantial information of our own against Chaplin, and we are not satisfied that there are reliable grounds for regarding him as a security risk.
"His name has, of course, been exploited in the interests of communism as one of the victims of 'McCarthyism'...
"It may be that Chaplin is a communist sympathiser, but on the information before us he would appear to be no more than a 'progressive' or radical."
Files released by The National Archives in 2002 showed that the British government blocked Chaplin's knighthood for nearly 20 years because of US concern about his colourful private life and political affiliations.
He was eventually knighted in March 1975 and died at his home in Switzerland on Christmas Day 1977, aged 88.
Below, see 40 amazing photographs of the silent film legend.