Gemma Arterton on Blitz comedy drama Their Finest: It was real time of liberation for women

London mayor Sadiq Khan introduces the premiere of wartime comedydrama Their Finest, set in the world of propaganda filmmaking during the Blitz. Gemma Arterton, Bill Nighy and Sam Claflin join director Lon Scherfig and other cast and crew on stage. Subscribe: Watch more on the BFI Player: Follow us on Twitter: Like us on Facebook: Follow us on Google+: