Video | King Colin, Oscars triumph for British actor

The film also won Best Film, and honours for Director and Best Original Screenplay.

In his acceptance speech, Firth thanked director Tom Hooper for his "immense courage".

Hooper said he had his mother to thank for finding him the King's Speech after she saw the play.

"The moral of this story is listen to your mother," he told the ceremony in Hollywood.

The film's writer, David Seidler, described how he has been moved to tears by messages thanking him for giving a voice to stutterers - of which he is one.

A heavily pregnant Natalie Portman took Best Actress for her role in Black Swan. In tears she thanked her parents and her fiance, who choreographed the film.

Welsh-born actor Christian Bale won Best Supporting Actor for The Fighter.

He said he was really touched that people thought he was worthy of his award.

Melissa Leo took the Oscar for Best Supporting Actress for her role in the same film, beating British actress Helena Bonham Carter, in The King's Speech.

Leo caused consternation by swearing, saying it looked so "******* easy" when she had watched a previous acceptance speech.

Later she apologised and said: "I really don't mean to offend."

"There's a great deal of the English language that is in my vernacular." 

Veteran actor Kirk Douglas came on stage to a standing ovation to present the best supporting actress award.

In other categories, Banksy lost out to Inside Job for Best Documentary.

The Social Network won for Original Score and Editing, and Inception for Sound Mixing and Visual Effects - a British win for Paul Franklin, Chris Corbould, Andrew Lockley and Peter Bebb.

Toy Story 3 took Best Animated Feature Film.

We Belong Together, the song from the film, won Randy Newman his second Oscar for Best Original Song. It was his 20th nomination.

In A Better World from Denmark triumphed in the Best Foreign Language category.

The Wolfman won best make-up.

Colleen Atwood took the Costume Design award for Alice in Wonderland - her third Oscar, having won previously for Chicago and Memoirs of a Geisha.

Strangers No More won Best Documentary Short Subject.

God of Love won Best Live Action Short Film.