Charlie Chaplin became the most famous man in the world – but did anyone know who he really was?

In the last years of the Great War, the world was in the grip of a pandemic. Its name was Chaplinitis. Outbreaks occurred everywhere. In the Cincinnati bank held up by a Chaplin lookalike. At American costume parties, where, the press reported, nine out of 10 men turned up, bow-legged, in baggy trousers. In Turkish newspapers, where the Little Tramp supplanted Uncle Sam as a symbol of the USA.

On the Western Front, where Army authorities banned soldiers from growing Chaplin moustaches. And in cinemas, where audiences crowded to watch the latest two-reel comedies by a small, wiry, English performer whose name everyone seemed to know, and who, thanks to a ￡670,000 deal with the Mutual company, was the highest-paid star in the world. Charles Spencer Chaplin had gone viral. “There is no known cure,” said one US newspaper, “except more Chaplin films.”

The Real Charlie Chaplin, a new documentary by Peter Middleton and James Spinney, starts with this epidemiology. “Almost instantly Chaplin’s on-screen character took on a life beyond his control,” says Spinney. “We find him in every aspect of popular culture: in songs, paintings, animations, comics, games, in endless imitators and impersonators. Even Chaplin’s own films were somehow unstable: they were so popular they were re-edited into new pirated works. The more you look, the more versions of Chaplin you find. It’s dizzying.”

The man himself was harder to detect. “When he looks out at us from the screen we feel an immediate intimacy with him. But off screen, people found Chaplin to be elusive,” Spinney explains. “His daughter Jane told us: ‘I grew up with the icon but I had no idea who the man was.’”

Chaplin seems to have liked it this way. He rarely wrote letters. He erased his London accent with elocution lessons. He was happy to exchange brief words with packs of reporters but disliked giving substantial interviews. At the beginning of his career, such encounters weren’t really part of film culture. Later, when the press wanted to quiz him about his supposed sexual interest in teenagers (guilty) or his rumoured involvement in revolutionary left-wing politics (not guilty), he had good reason to keep them at bay. For one of the key figures of the last century, there is surprisingly little footage of him speaking candidly.

Middleton and Spinney’s solution to this problem was one pioneered by the Wallace and Gromit animator Nick Park, when he synchronised the movements of plasticine animals to human interviewees in Creature Comforts (1989).

In the archive of the Oscar-winning filmmaker and movie historian Kevin Brownlow, the directors found a vivid audio interview that Brownlow had recorded with Effie Wisdom, a childhood friend and neighbour of Chaplin. Two actors were then filmed lip-synching to the tape. Middleton and Spinney (who had used the same trick in their 2016 film, Notes on Blindness) did a similar job on an interview Chaplin himself gave to Life magazine in 1966 – and on the audio of a notoriously hostile press conference conducted by Chaplin on the release of Monsieur Verdoux (1947), when J Edgar Hoover’s FBI was attempting to expose the comedian as a secret Communist.

“Only a fragment of the recording was thought to survive,” says Spinney, “but a long search led us to the original reels stowed away in a lockup in San Francisco.” The results, after a thorough digital clean-up, are spookily persuasive. That mixture of tenacious research and dreaming reflects something fundamental about the study of Chaplin. For those of us who toil in this seemingly inexhaustible field, new vistas are always opening, while significant areas remain stubbornly blank.

Only a few weeks ago, a Vietnamese Twitter account I follow started posting photographs of Charlie hanging out with a bunch of journalists in Hanoi, during a visit in 1936 while on honeymoon with his third wife, Paulette Goddard. This led me to some Vietnamese newspaper articles that seem barely to have been touched by Chaplin scholars.

In one, Thach Lam, a journalist for the satirical magazine Phong Hóa, asked Chaplin – or Sác L? as he was known in Indochina – about his new picture Modern Times. Chaplin described the plight of the hero, a production line worker reduced to a twitching, traumatised state. “In our land,” replied Thach, “there’s no machinery, no factories at all.” In other words, First World problems.

Contrast that level of detail with the big blank space in Chaplin’s biography: the absence of a birth certificate. It’s assumed that he was born in south London in 1889, but there is no paperwork to prove it – much to the annoyance of the FBI, which, in the 1950s, asked MI5 to check if Chaplin was, secretly, a Jew named Israel Thornstein. In 1915, Chaplin – or a publicist acting on his behalf – claimed that Fontainebleau in France had been the place of his birth.

And there’s evidence to suggest that this ambiguity nagged at Chaplin himself. On a visit to the family estate in Vevey, Switzerland, in 2011, Charlie’s son, Michael, told me the story – how his younger sister, Victoria, had prized open a locked drawer in their father’s bureau to find a letter written to him in 1971 by a man named Jack Hill. “Charlie,” it read, “this is not someone trying to blackmail or extort money from you. I have no use for money. I think I am the only one alive who can tell you what you have been wondering about for so many years.”

Hill explained that he had been reading Chaplin’s memoirs and was puzzled by his claim to have been born in London. “You were born in a caravan so was I,” he wrote. “It was a good one it belonged to the gipsy Queen who was my auntie you was born on the Black Patch in Smethwick near B’ham so was I…” Michael described this in hushed tones. We were speaking in the room in which his father had died.

The following year, Michael got in touch to say that he and his wife Patricia were planning a pilgrimage to the place mentioned in Hill’s letter, an area of common land now known as Black Patch Park. On a showery July morning we met with a local historian, Ted Rudge, and Jack Hill’s 96-year-old daughter, Ivy Deaville. Ted told us about conditions on the Black Patch, then a barren parcel of land heaped with waste from local foundries, and the life of Queen Sentinia Henty Smith, who, from her caravan, presided over a community of 300 families. Ivy spoke about her father’s Romany heritage and said that he wasn’t the type to send prank letters: if he thought Chaplin had been born in Smethwick, he was sincere. Michael looked wistfully around, enjoying the stories, the possibilities. “Perhaps it’s true,” he said. “Why not?”

The walk back to the railway station was just as evocative. Foundry Lane, once a drag of busy mills and factories, is now a row of industrial ruins. I peered into the carcass of an old works where X-Ray tubes were once manufactured. There were still crates piled up inside, as though the staff had just clocked off. A century ago, this was the world of Chaplin’s audience – the industrial workers who occupied the real-life equivalents of the tenements and dead-end streets of his cinema. The original hosts of Chaplinitis.

The biggest, weirdest spike in Chaplinitis cases is reported to have occurred on Nov 12 1916. psychical phenomenon in “Chaplin wave” which swept united states, blared the Lincoln Star, sharing the details of a mass Chaplin hallucination. Charlie’s name, it claimed, was paged in the lobby of 800 respectable hotels. Crowds turned up at railway stations, expecting him to step off the next train. Sightings were recorded from the Atlantic to the Pacific coast and from the Canadian border to the Gulf of Mexico. A circular issued by the Boston Society for Psychical Research concluded that this was the result of “a sudden mental impulse manifesting itself simultaneously practically throughout the length and breadth of the land”.

It’s mentioned in David Robinson’s definitive biography, Chaplin: His Life and Art (1985) and it’s the starting point of Sunnyside (2010), the Chaplin novel by David Glen Gold, and of Spinney and Middleton’s documentary. Search the cuttings, however, and all these stories lead back to that single article in the Lincoln Star and its quotes from the paranormal researcher Sir Bamfyle More Carew [sic]. If your bulls--- detector is twitching, take a lollipop. The Boston Society for Psychical Research was not founded until 1925. And despite his avowed eminence, Sir Bamfyle published nothing on paranormal phenomena, nor anything else – probably because he seems not to have existed at all.

Over a century later, it’s hard to say whose joke this is. But the Lincoln Star gives us a clue. Its authority, we’re told, is a direct descendant of “the most famous gypsy convert in the world’s history”. The name is slightly wrong, but this means something. Sir Bampfyle Moore Carew was an eighteenth-century con artist whose memoir describes how he ran away to join the gypsies, who crowned him King of the Beggars. Jack Hill would have been amused.

“It’s a wonderful story,” says James Spinney. “As you say, in factual terms, it seems to be untrue. But it captures something that’s in the air at that moment. In some ways, Chaplin was in all these different places at the same time. Through the Tramp, he was looking out from the screen at audiences throughout America and across the world simultaneously. This type of fame hadn’t existed before Chaplin.”

In 1916, Chaplin wasn’t merely famous. He was fame. The fever of that moment has now passed, but his image – that pictogram of moustache, hat, cane and kohl-rimmed eyes – is still one of the most recognisable in the world. The pandemic is over, but the virus remains. We live with it.

The Real Charlie Chaplin is released in cinemas and digitally from Friday February 18