Broken Social Scene, Heaven, London

"When you're in a band, you get on stage and suddenly everyone's louder and crazier. That's generally the idea with Broken Social Scene," says Kevin Drew, the singer, guitarist and founding member of the sprawling Toronto indie-rock collective that is Broken Social Scene. The strength of that idea is certainly apparent tonight; it's live that they become a real force.

For the past 10 years, Drew and co-frontman and bassist, Brendan Canning, have been assembling their musician friends to write and perform music, with well-known names from the local Canadian indie rock scene – Leslie Feist, Emily Haines of Metric and Amy Millan of Stars included – floating in and out. At their busiest and most cacophonous tonight, during their final song, "Meet Me in the Basement", from their new album, Forgiveness Rock Record, they are 15, including a brass section, violin, several guitars, keyboards, drums and multi-vocalists. Canning still finds the space to leap up and down; it's loud and it's certainly crazy. Broken Social Scene's songs boast shambolic rough-around-the-edges charm, but all the while the often cacophonous instrumentation is in the service of the song, and never slips into the territory of indulgent jamming.

The effect on the listener throughout their near two-hour set is liberating, especially on the exuberant "7/4 (Shoreline)" from their eponymous 2005 album. It's here and elsewhere that they merge the shimmering guitars of post-rock and the melodic punch of indie rock to compelling effect.

"Late Nineties Bedroom Rock For the Missionaries" builds up to a frenzy of guitars. Still, amid the bursts of exuberance, some of their best moments are their more spatial and shoegazey songs. "All to All" is a melodic indie-pop standout, Lisa Lobsinger's airy vocals ringing out like Liz Fraser in The Cocteau Twins, over restrained, twitching guitars and plaintive violin. With this much passion and drive, you can't fail to be uplifted.