Staunton played a cleaning lady, who secretly carries out abortions in the low-budget film, the BBC reported Saturday.
"I want to thank the tireless jury for embracing and honoring this film which I'm so proud to be in, because it deals with a complex subject with such compassion," Staunton said.
Mike Leigh, director of "Vera Drake" thanked the jury, which included Helen Mirren, Scarlett Johansson, Spike Lee and director John Boorman, for their "excellent decision" and the U.K. Film Council for its support.
"In a cynical world it is a wonderful thing and most reassuring when low budget, serious, committed, independent, European films are recognized and encouraged in this way and helped to reach their audience," he said.
Spanish actor Javier Bardem won the best actor award for his portrayal of a paralyzed man who wants to kill himself in "Mar Adentro."