Blethyn's first film in two years, Rachid Bouchareb's "London River" opened at the 59th Berlin International Film Festival in 2009 where it won a Special Mention by the Ecumenical Jury. In the film, for which Blethyn had to learn French, she portrays a mother waiting for news of her missing child after the London bombings of July 2005, striking up a friendship with a Muslim man, whose child has also disappeared. Blethyn, who had initially felt sceptical and reticent about the film due to its background, was originally not available for filming but Bouchareb decided to delay filming to work with her. Upon release, the film received favourable reviews, particularly for its "dynamite acting". Mike Scott from "The Times-Picayune" commented "that Blethyn's performance is nuanced [...] it's that performance—at turns sweet, funny and heartbreaking—that ultimately draws viewers in and defies them to stop watching".