This is a nice idea, nicely executed. Fringe veteran Barry Castagnola has overslept for his own show, so a number of alter egos fill in until he gets there – so far, so standard for a character showcase.

But a combination of great creations, sharp in-jokes and a film showing his progress through the streets of Edinburgh as he simultaneously attempts to find a stand-in combine to make a hugely entertaining show.

Those in the audience who don’t know the set-up are genuinely perplexed when the announcement of Castagnola’s name is met with a flurry of activity from the venue staff; ‘He’s not here yet!’ Nonetheless one of them, Figgsy, is persuaded to play one or two of the tunes he’s written to kill some time.

This is actually the weakest character in the show: a typically earnest if naïve studenty protest singer offering the unique insight that war is wrong. His second tune is a love song that goes all stalkery, a tired old cliché of musical comedians – which is something of a surprise given that for the rest of the show Castagnola cheerfully makes a bonfire of such trite conventions.

Indeed, the next character is newish comic Danny Donkin, employing all the tropes of the comedy-course graduate. He has does jokes based on his parents’ nationalities, has trademark poses he thinks will get him on E4, and alternates between gag-free oddness and saying ‘awkward!’ in lieu of a punchline. When it’s parody it’s funny in a way that all the real-life hopefuls only rarely are – and this is a welcome tonic for anyone who’s seen too much inauthentic youth-skewed comedy this Fringe.

More insider gags from the next character, a brash, apparently coke-fuelled agent bellowing gags of his own, reliving his days as an old-school act of dubious taste. There is actually some decent, if bawdy, material here – proving Castagnola’s not just mocking the business, but can actually write jokes too.

The next archetype to be mocked is the super-keen Oxbridge student improvisers/sketch group, with their wide-eyed hopes and dreams; daddy’s financial backing; and arsenal of theatrical warm-up exercises… if no actual talent. Castagnola nearly ruins the artifice by ad libbing a half-decent pun he’s forced to play down, but there’s more silly fun here.

Between the characters, and sometimes interacting with them, we see the ‘real’ Castagnola’s dash to the stage in a film filled with cameos from his comedian chums – cue more in-jokes – and offering a narrative to the hour. There’s also a completely odd character who drops in at the end with no context, funny for his sheer oddness.

Castagnola’s writing is decent enough on its own, but this is primarily a show for people who are immersed in comedy… so  Edinburgh’s probably the only place this state-of-the-industry satire would work to its full advanage. If you’ve already seen just one too many lacklustre comedy show, this is the antidote.