What's the noise you keep hearing while watching Irvine Welsh's play? Laughter? Not so much. It's more likely the terrible creaking of a woefully old-fashioned script, co-written with Dean Cavanagh.

We're in the scruffy office of a film company in Soho in 1969, belonging to film director Donald Cammell, who really did want to use real gangsters in his cult movie Performance. Performers imagines the audition process, a promising set-up that's rapidly squandered. Besuited Lahndahn hardmen, a sleazy Bert and a chummy Alf – played by George Russo and Perry Benson, both better than the material – turn up to see what this movie-making malarkey is all about. The perky teenage receptionist – a dolly bird in a beehive and white patent leather boots, because you better believe the clichés will extend as far as footwear – turns out to be Alf's niece and Bert's recent drunken squeeze.

He didn't know she was only 16, honest guv, but the blackmail plot that briefly flourishes between the squawking teenage girl and the dim gangster soon just sort of becomes… not that relevant. We swerve into a strange interaction between the two men and a posh, right-on hippie assistant director named Crispin, dressed in – yup – flares and a waistcoat, who bangs on about Borges and Francis Bacon and Art with a capital A. Bert, predictably, thinks such stuff is "a load of old bollocks" and that Bacon is a "fanny merchant". Devastating stuff.

But much of this mercifully brief show is just hackneyed gangster chat. It aims for that banality-with-a-bite thing you got in a host of Nineties gangster movies, but really just proves pretty dull. There's little panache, and the pacing is off in Nick Moran's production; lines seem to move past each other rather than hitting a target, and few jokes raise more than a titter. There's also a basic difficulty in hearing some lines in this admittedly echoey venue.

Queasily, many of the jokes also rely heavily on racist, sexist and homophobic sentiments or terms that used to be the norm in the Sixties. These are never problematised, questioned or even really engaged with; one suspects that, cripes, Welsh thinks he's being edgy simply by including them. There is a brief, glimmering moment when it looks like the gangsters' protests-too-much homophobia may be effectively turned on its head: Crispin becomes weirdly insistent on the men taking their clothes off for a screen test, and there feels like there could be something subversive about to occur.

But nope, this plotline doesn't go anywhere either – really, it seems like the whole thing is constructed just so Benson can get naked. That's the punchline... 'fat man takes off clothes'. As any of Welsh's other characters might say: what a load of shite.

Performers runs at the Assembly Rooms until 27 August.

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