Grassroots, BFI London Film Festival

Grassroots, BFI London Film Festival (KELLEY VAN DILLA / SAMUEL GOLDWYN FILM)

With the US election coming up, it's no surprise that there are a few films focused on the ballot box about at the moment. Seal Team Six: the Raid on Osama Bin Laden will be distributed by movie mogul Harvey Weinstein two days before the presidential election; meanwhile the Will Ferrell and Zach Galifianakis spoof The Campaign is out now, lampooning the race to office as a dirty farce.

Grassroots is not nearly so self-important nor so farcical. In fact, the new Jason Biggs film takes its title so seriously that director Stephen Gyllenhaal (father of Jake and Maggie) has taken to screening it at campaign events for "grassroots" candidates around the country.

Gyllenhaal's script is based on the memoirs of a real life affair in Seattle in 2001, when a freelance music journalist stood for local office against a longtime incumbent, his sole policy being the extension of the city's monorail. Despite no political experience, something in his impassioned speeches caught the imagination of students and other locals.

Played here by Joel David Moore, Grant Cogswell is, unfortunately, a whiny social outcast whose accidental leadership is difficult to believe in. There is more solid characterisation in Biggs as Phil Campbell, his ex-journalist friend turned campaign manager, although just how much managing he actually does is questionable.

Biggs' American Pie routine - geeky nice guy stepping out of his comfort zone - has stuck with him for a reason. He is great here as the reluctant idealist torn between sense and optimism, even when his well-meaning girlfriend tires of the campaign banners and thoughtless students that now litter their flat.

Cedric the Entertainer as the incumbent whose seat Cogswell covets, treads a nice line too between complacent and concerned. Is he really the corrupt grandstander Cogswell makes him out to be? Or just a politico in need of a wake-up call?