Andrew Haigh has won the Best British Film award at this year’s Edinburgh Film Festival with 45 Years, about a troubled marriage. The film stars Tom Courtenay and Charlotte Rampling, who shared the award for Best Performance in a British Feature Film with James Cosmo for his performance in The Shammassian brothers’ The Pyramid Texts.

The Michael Powell Jury was chaired by LA Times film critic Kenneth Turan, who called 45 Years “a quietly explosive film which represents classic filmmaking at its best. This is a measured yet provocative film, a masterclass in understated acting that was the unanimous choice of the jury.”

Other winners included Marielle Heller’s The Diary of A Teenage Girl, which won Best International Feature film. As Deadline exclusively revealed, Heller is now attached to direct Natalie Portman in Supreme Court Judge Ruth Bader Ginsberg biopic On The Basis of Sex.

Crystal Moselle won Best Documentary for The Wolfpack, while Mike Hoolboom’s Scrapbook won Best Short Film and special mentions went to Juliana Bao’s performance in Maruani Landa’s Cipriani and Ahmet Simsek’s performance in Jannis Lenz’s Shadowboxer.

The festival closes Sunday night, when the Audience Award will be revealed.