“Tonight we’re Mclusky, even if it’s in inverted commas,” says frontman Andrew “Falco” Falkous, addressing a feverishly excited crowd packed into the tiny Buffalo Bar, which is due to close soon after 14 years of staging new bands.

These days, Falco is part of the excellent and incendiary noise-rockers Future of the Left. Tonight, though, as a reaction to the unsettling nationwide trend of important small venues being needlessly shut down, he’s reunited his old band (well, kind of: Falco and drummer Jack are joined by Future of the Left’s Julia Ruzicka on bass and St Pierre Snake Invasion’s Damien Sayell, who sings Jon Chapple’s parts). Mclusky recently raised money for Newport’s Le Pub by playing two gigs, one at the venue itself and another at Cardiff’s Clwb Ifor Bach. Now they’re doing the same for the London venue they’ve “played a lot of times over the years”.

The post-hardcore group may have split in 2005, but their reputation has grown in their absence. Witty, acerbic and brutal, it’s often hard to comprehend why they weren’t bigger. That said, it’s just as hard to imagine a packed stadium singing the closing lyrics of She Will Only Bring You Happiness – “Our old singer is a sex criminal” – back at the band, as the crowd so enthusiastically do here. Mclusky tear through Dethink to Survive and Collagen Rock; as they do, 150 people move in unison, a tangled mass of bodies. Sayell joins in with the mayhem, lying on the ground before the band launches into Chases, beckoning the crowd to him.

As the show hurtles to its conclusion, soundtracked by To Hell With Good Intentions, it’s the perfect reminder of why we need small venues like the Buffalo Bar: they help new bands create their legend. Tonight, Mclusky remind us of theirs.