The popular drama about King George VI's seemingly insurmountable stammer swept the ceremony at the Royal Opera House in London's Covent Garden, with seven awards.
These included those for Best Picture, Actor Colin Firth, Supporting Actor Geoffrey Rush, Supporting Actress Helena Bonham Carter and Original Screenplay writer David Seidler.
For Firth, it was a back-to-back victory. He also won last year for A Single Man, about a gay man mourning his late lover. "I like coming here," the Oscar frontrunner told the Bafta crowd, eliciting a laugh. He also paid tribute to his beautiful Italian wife Livia Guiggioli, saying, "I would like to thank Livia and the whole family for remaining so steady, whether they are dealing with a dancing queen or a sometime king."
Natalie Portman was named Best Actress for Black Swan – though her pregnancy prevented her from flying to London – while David Fincher won as Best Director for The Social Network, which also took awards for its Adapted Screenplay by Aaron Sorkin and for its Film Editing.
Both Firth and Portman won Screen Actors Guild Awards last month, another sign that they will likely take home Oscars.
"I'm so used to losing its quite a strange feeling to win, but it feels very nice," said Bonham-Carter, who plays Queen Elizabeth (the Queen Mum) to Firth's King. "Although, of course, children, if you are watching it is not about the winning."
Sorkin said, "Normally I'd be excited about this, but sitting in the seat in front of me was one of the Beatles."
Sir Paul McCartney had presented the best score award, to The King's Speech.
Reporting by PHIL BOUCHER