Joshua Oppenheimer's The Act of Killing has won best documentary at the 2014 Bafta awards. "It is helping to catalyse a change in how Indonesia talks about its past," said Oppenheimer in his acceptance speech, adding that "the media and public are talking about the moral catastrophe" of the genocide in Indonesia the film depicts.

He highlighted British and American involvement in the crimes of the country's warlords, saying they have "collective responsibility" for "participating in and ignoring" the crimes. He thanked only his anonymous co-director, who couldn't appear because of the secrecy needed to protect him.

The Act of Killing was voted the best of 2013 by Guardian critics, and is up for two awards at this year's Baftas: best documentary and best foreign-language film. It is considered a frontrunner for the best documentary film awards at the Oscars on 2 March.

• The winners as they are announced
• Xan Brooks is live-blogging the ceremony here