From then on, he increasingly sought control of every aspect of the production of his films, culminating in a deal in 1917 with First National Film Corporation which gave him the artistic freedom he was to enjoy for the rest of his career, ultimately with United Artists, which he co-owned, and for which he made such classics as The Gold Rush and Modern Times. He was the ultimate control freak, sometimes demanding 50 takes of a scene before he was satisfied, and reducing his actors to despair in the process. 

His private life was not dissimilar: he was an incorrigible womaniser with a penchant for very young girls, and he treated almost all of them appallingly. When he was asked to describe his ideal woman he replied: "I am not exactly in love with her, but she is entirely in love with me." He married his first wife, Mildred Harris, when he was 29, she 16, and then only because she (untruthfully) told him she was pregnant. In the event, she soon was but the baby died soon after birth. The couple were divorced a year later amid lurid revelations about his cruelty to her. Exactly the same scenario occurred with his second wife, Lita Grey, who was also only 16. She too became pregnant, and Chaplin (who was simultaneously conducting an affair with Rebecca West) was forced to rush into marriage or face 30 years in prison for having sex with a minor. After the wedding, he went fishing. The marriage lasted three years before ending in even more scandalous allegations about his conduct. The pattern continued into his fifties: he first had sex with his fourth (and final) wife Oona O'Neill when she was 17 and under age; she was 36 years his junior. Even after he married her when she turned 18, he went on trial for transporting another young woman, Joan Barry, across state lines for immoral purposes; he was acquitted but was adjudged at a subsequent trial to be the father of her baby daughter.

By 1952, the Tramp was history and increasing public hostility plus the threat of action against Chaplin for his apparent sympathy for Communism came to a head: when he and his young family were two days out to sea on the Queen Elizabeth, bound for England, his US re-entry visa (he was still a British citizen) was rescinded. He ended up in Switzerland and would not return to Hollywood for 20 years.

Ackroyd has written a model biography, as crisp and succinct as a Chaplin two-reeler. He calls Chaplin a visionary; he was a brilliant innovator and storyteller (though I preferred Buster Keaton). But who remembers Chaplin today, a hundred years after he stood at the height of his fame? Young people know little about him; his films are rarely shown on television, despite the multiplicity of channels. It is an interesting paradox that the first genius of the revolutionary medium of cinema should now be almost forgotten, while Dickens remains as popular as ever.