The movie, starring Gary Oldman and John Hurt, was named the night's Outstanding British Film and its co-writers Peter Straughan and his late wife, Bridget O'Connor, won the Best Adapted Screenplay prize.
Meanwhile, Hurt received the Outstanding Contribution to Cinema Award at the ceremony in London.
Meryl Streep was named Best Actress for her role as former British Prime Minister Margaret Thatcher in The Iron Lady, and Jean Dujardin won Best Actor for black and white silent movie The Artist, which also landed Michel Hazanavicius Best Director and Original Screenplay trophies and awards for cinematography, score and costume design.
The Best Supporting Actor and Actress prizes went to Oscars favourites Christopher Plummer for Beginners and Octavia Spencer for The Help.
And motor racing biopic Senna, which chronicles the life and career of tragic Formula One driver Ayrton Senna, was also among the night's big winners. It won the Best Documentary award as well as a Best Editing prize.
Martin Scorsese's Hugo was also a double winner, grabbing Best Production Design and Best Sound honours.