Caught Live: Bombay Bicycle Club @ O2 Academy, Sheffield

When I Had The Blues But I Shook Them Loose, Bombay Bicycle Club’s debut LP, dropped a little over two years ago, it was viewed in some circles as verging on indie-by-numbers. That judgement was maybe a touch harsh on the North London outfit, but the record's modest position of number 46 in the UK charts seemed to confirm the belief that here was band who were quite content to cling on to the coattails of what had become a largely stale and lifeless genre.

And yet, here we are are approaching the end of 2011, and BBC have not one, but two top-ten albums to their name, not to mention a recent NME front cover, along with this evening's sold-out O2 Academy gig. With tens of thousands of fans old and young – tonight's is one of many all-ages shows on the band's current UK tour – you might be forgiven for wondering how they've managed to transform themselves from also-rans to pacesetters. Last year's Ivor Novello-nominated sophomore outing Flaws was a purely acoustic affair, a gamble that paid off and perhaps unexpectedly propelled Jack Steadman and co. into the limelight; but although August's third full-length, A Different Kind of Fix, manages to combine these two different sounds, it leans far more closely to I Had The Blues...'s out-and-out indie template than to the more melodic, stripped-back sensibilities of that album's follow-up.

Emerging tonight to the opening strains of summer single 'Shuffle', BBC – who are intermittently joined by folk singer Lucy Rose on backing vocals – launch into a twenty-song setlist. It’s unsurprisingly heavy on new songs, but also features a brace from Flaws: the lovely 'Ivy & Gold', along with album-opener 'Rinse Me Down', which acts as an acoustic interlude in the middle of the gig. Although we might have been expecting to hear a few more tracks from what constitutes the band's breakthrough record ('Dust on The Ground' does feature, but in its original, electric form), the bigger surprise is arguably the appearance of 'Open House', a track lifted from their 2007 debut EP. It was written and recorded when the band were all still in their mid-teens, and tonight this really shows. It lacks the weight of what would soon follow on I Had The Blues..., as well as being woefully formulaic compared to newer songs like 'Still'. This (indisputably) Radiohead-inspired effort is performed by Jack and Lucy alone onstage, and serves as a segue into a two-track encore. Although haunting, it does seem a little out of place tonight, and compared to a lot of what has just come before – the kids jumping around to 'Always Like This' minutes previously, for instance – it sounds somewhat lost to these ears, momentarily threatening to derail the show's momentum until 'What If' arrives to rescue the situation.

In effect, this uncomfortable clash of styles serves to highlight the pitfalls of BBC’s admirable willingness to push their sound by embracing different genres. Their ability to really get the crowd going and singing in unison (“Dreaming of you / Pushing up to me...”) during the five-minute 'Cancel on Me', and then get them swaying to the melodic acoustic numbers that follow, is a testament to their success. And yet, there are times throughout the evening when the overall effect is both alienating and disjointed. The fact that one of the most moreish tracks on A Different Kind of Fix – the awesome, repetitive slow-builder 'How Can You Swallow So Much Sleep', which opens the record – feels so out of place sandwiched between 'Lamplight' and 'Magnet' is testament to these shortcomings.

But when it does all gel correctly, which it does on several occasions this evening, the results are undeniably impressive. The aforementioned 'Shuffle' and 'Ivy & Gold', along with early single 'Evening/Morning', all provide highlights that immediately have the crowd dancing and singing along, to the obvious enjoyment of the band. Bombay Bicycle Club prove tonight that they can put on one hell of a show; it would just be so much better if they could decide exactly what kind of one they want to put on.

A couple of nights after their O2 Academy performance, our photographer Duncan Elliott made it along to the band's similarly sold-out Manchester Apollo show. Go here to view a full gallery of his shots from that gig.

Bombay Bicycle Club have a brand new single, 'Lights Out, Words Gone' (video below), out this week. Their UK tour finishes up at Brixton's O2 Academy on Wednesday, but the band are due to play Belfast, Cork and Dublin in early December. Full details here.