As one wanders round the 100 Club before anyone takes the stage, it is impossible not to feel as if tonight is going to be somewhat confusing. A legendary punk venue in its own right, this place has more seen legends come and go over the years than most.

Why, then, is a band like Future Of The Left scheduled to play? Theirs is not a legendary heritage. They've only released one single. They've only played a handful of gigs, frequently under different aliases. What gives them the right and the status to play here, within these apparently hallowed punk halls?

Oh I'll stop being obtuse, it's obvious. Two thirds of them used to be legendary, when Mclusky were hot property. But now, with singer Andy Falkous publicly denouncing any remaining artistic links between old and new, it seems slightly strange for a band as young and in its infancy as Future Of The Left to immediately be at home in the 100 Club. Why should they immediately be in the position that Mclusky had to work for? Slight case of double standards, perhaps? Oh well.

Kong take the stage and shit everyone up. Donning extremely confusing masks that seem only to jar their actual appearances in a monumentally disturbing way, they rattle, spit and ping their way through what the man in front of me described on his phone as 'math-thrash'. That's a fair assessment. Ludicrously well-practised smashes of noise are flung out like darts of silly string, accompanied by the kind of bass gymnastics (oh yeah, the bassist is wearing only his mask and some tiny pants) that could make a clothed man blush, such is their skin-slapping ferocity. Like Shellac tuned down to a sexy bass groove with occasional yelps, Kong freak people out as much as they make them laugh. That's a tricky line to straddle.

Future Of The Left arrive to great jubilation, and launch immediately. They don't come down to earth again for a good 45 minutes. Breathlessly careering through the sing-along-a-shit-storm that is 'The Lord Hates A Coward' (never have the words "violence solves everything" been so white-funk and catchy) and loads of other instant classics, Falco and co. are clearly having fun. Which is their whole shtick, really. Falkous has always sought to exhume his fury through pithy and scathing humour, leaving listeners with the sense that the issues he raises are so plainly confrontational that the only thing left to do is to slap a Groucho Marx mask on them. With his former band, these issues seemed easier to confront. There was always a joke to be made about hipsters and politicians, always a finger to be pointed at the blatantly inhuman. With Future Of The Left, though, we get a dilution of this. A song about Falco's cat is comically insane and overblown, but devoid of the ringing truth of the more serious tunes. But then again, wasn't Mclusky's 'Gareth Brown Says' just about an annoying twat from primary school?

Thankfully, the searing opinions return to the fore in a song dedicated to "any Tories in the room", resulting in some scintillating vocal homophony, as punchy and satisfyingly ballsy as anything else this evening. As the set blisters on, voices are heard to be quoting Mclusky lines, drunkenly pining for the old days. When they get increasingly more derogatory, bassist Kelson Louis Tregurtha Mathias instantly counters: "Fuck me? You paid a fiver to get in. Fuck you. I have to go to work tomorrow, I don't give a fuck what you say." It's nice to see that this comes from the only non-alumnus of Mclusky. In the encore that follows, Kelson leaps into the audience in a ball of sweat, Falkous shrieks like a banshee bitch and drummer Jack Egglestone has his kit removed from around him piece by piece as he haphazardly tries to complete an epic drum solo. Ending in the sound of nothing but applause, this deconstruction forms a perfect end to a set wracked with destructive energy and odd atmospheres.

If you're one of the many people that invariably compare them to Mclusky, Future Of The Left still have a way to go. But for now, they are brutal entertainment and fiery defiance. Exactly what you'd expect in this venue.