Bombay Bicycle Club, Heaven, London

A couple of years ago, Bombay Bicycle Club were at the forefront of the underage band scene, alongside their school peers Cajun Dance Party. Still just 19 years old – the band only finished their A-Levels last year – it's apparent tonight that while their devoted young fans who have grown up alongside them are still present, their audience has expanded to include all ages.

It's no surprise. The north London band boast a maturity in their performance and their sound which blends the lo-fi post-punk of Pavement and Sonic Youth and the catchy guitar riffs of The Strokes. Since they won a Channel 4 battle-of-the-bands competition in 2006, and played the V Festival that year, they have been steadily building their fanbase, and this summer they released their acclaimed debut album I Had the Blues But I Shook Them Loose.

It's live that their energy comes to the fore, due in part to their singer Jack Steadman's unfaltering passion. While his three bandmates thrash it out frenetically on guitars and drums, intensity and emotion bubble up through Steadman into constant smiles, flailing arms, and a quivering voice recalling Conor Oberst, with refreshingly youthful excitement rather than angsty despair. It must be a challenge not to smile, faced with a room packed full of fans loudly singing back your lyrics.

Although the band wear their indie rock and post-punk influences on their sleeves, it's their exuberant delivery, catchy hooks, danceable rhythms and constantly evolving time signatures that compel. The skittering drum-and-guitar opening of "Evening/Morning" bursts into a bass-driven clattering beat that places vocals on the sideline. "Always Like This" builds up to such a satisfactory anthemic melody, with Ed Nash's skipping bass line recalling Vampire Weekend, that the crowd burst into applause. The shimmering guitar interplay between Steadman and Jamie MacColl stands out; their hooks sear through "Magnet" and "Dust on the Ground". Fed through effects pedals, they take on even more of a euphoric ambient feel live than on record.

Interesting that the band have musical heritage in their blood – guitarist MacColl is the son of folk musician Neill, and Kirsty MacColl was his aunt. That Bombay Bicycle Club are preparing to turn to Appalachian folk points to an exciting future of limitless possibilities ahead.