"It doesn’t say anything about that on the ticket," says my friend Barry indignantly, when I remind him that we should probably make an effort for Arcade Fire’s show tonight. "Maybe I’ll put on my nice shoes instead of trainers." This is what most men I know mean when they say they’ll be wearing "formal attire", let alone "costume", both of which have been Arcade Fire’s mandatory dress code for their comeback shows in New York and in the UK. 

  In London, though, these requirements result in a scene that’s halfway between Bacchanalian ball and an accountants’ conference. There are tall men in suits and fedoras everywhere. I am stood between a cuddly shark, a troupe of wizards in sequinned capes, two women who appear to be wrapped in tinsel, and Barry’s shoes – impressive for a Tuesday night in Camden.  

The effect of all this is both bizarre and magical. Arcade Fire could easily sell out a string of shows at a soulless stadium and bang out their greatest hits, but instead they’ve decided to bill themselves as "fake band" The Reflektors, fanny around in giant papier-mâché masks, and throw a bunch of smaller arty-party happenings. Like The Knife's live show this year, in which they abandon their instruments and start jumping around in formation routines, they really just want you to lose yourself to dance and become the show yourselves.  

So we do. Ringleader Win Butler flounces onto the stage in a gold dinner jacket and a cross between a mirror ball and a paper bag on his head, launching the 10-piece band straight into ‘Reflektor’. It sets the tone for Arcade Fire: The Next Generation, a mix of "Studio54 meets Haitian voodoo" that overlooks most of their hits in favour of foot shuffling tropical-disco and hypno-bongo grooves locked down by a powerfully precise rhythm section. Some guys in smart three-pieces start to pull moves they never knew they could.

Despite the Studio54 comparison, however, Arcade Fire’s performance isn’t some intense cosmic rave; it doesn’t lock you in like a DJ set. It's more of a Warholian freakout with the kind of new-wave party music that Bowie would have pulled on his glittery platforms for in the late-70s. ‘Joan Of Arc’ has an orchestral glam-rock stomp; ‘You Already Know’ – their most straightforward new track – appears to channel cor-blimey indie-ska; and 'Flashbulb Eyes' has echoes of dub. They even do a cover of The Clash's 'Bored Of The USA' and dedicate it to Don Letts, the iconic reggae/punk DJ who plays records after the show.  

The band, meanwhile, look like they're having the most fun of all. When Butler's fellow ringleader Régine Chassagne isn't bashing a steelpan, she's weirding up 'Sprawl II (Mountains Beyond Mountains') by twirling ribbons in the air. When the newly added – and, quite frankly, superb – Haitian bongo players aren't pitter-pattering, they're shaking glittery pom-poms. And when violinist Owen Pallett (aka Final Fantasy) switches to keyboard, he pretends to slap himself in the face in mock horror.   

You could argue, of course, that these theatrics detract from the music. But it swells in the right places with the epic grandeur that Arcade Fire does so well. As Butler dedicates the gracefully disco-fied 'Afterlife' to gay marriage and it segues magnificently into the New Order-rivalling bassline of 'It's Never Over (Oh Orpheus)', the molten energy makes the room erupt. All the clichés you could ever dream up about having an intensely awesome time are in full effect.   

If Arcade Fire’s new show has taught me anything tonight, it’s that indie gig-goers’ attempts at fancy dress are pitiful. But it’s also proved how much more special other live performances would be if they were less of a gig and more of a party. If only more bands did something as batshit bonkers in pursuit of a good time, and made us look like bellends, and put on shows that make my mate Barry wear his posh shoes again and again and again.