When Richard Peppiatt resigned from the Daily Star in March 2011 he decried its racist and prurient agenda in a brilliantly written resignation letter to Richard Desmond who was reliably informed of the “cascade of shit pirouetting from [his] penthouse office, caking each layer of management, splattering all in between”.

The Star hit back, instructing a big PR firm to smear its principled cub reporter. Then came the threatening texts: “You’re a marked man until the day you die” and “RD will get ya”.

But rather than limp off back to the regions to report on cats stuck up trees, the 27-year-old Warwick graduate gave evidence to the Leveson Inquiry and then buckled down to pen a show that, to quote the publicity, places him firmly “outside the tabloid tent pissing in”. The clever title is thus as much a reference to News International’s disingenuous defence of phone hacking as to Peppiatt’s own decision to rove off into the wilderness beyond the Fourth Estate.

The result is a rich seam of heartfelt, original and energetically delivered material which provides an effervescent pick-me-up for sufferers of Leveson Fatigue. Whilst Peppiatt says it “needs a lot of work”, if the applause after a first performance dogged by technical problems and a lack of air conditioning above a pub in Battersea is anything to go by, the signs are looking good for the final production that will run at the Edinburgh festival from 1 – 27 August.

If stage success comes, it will be because, rather than resting on the laurels of his ability as a writer and participation in Leveson, Peppiatt has really buckled down to select, structure and write his material. Any Thomases who doubted him are sent packing in the first few minutes with a pithy comic cut of footage from the Leveson Inquiry in which – in response to the question “Whose fault is it then?” – everyone blames The Guardian while the Murdoch record sticks on “I don’t remember that at all”. Towards the end, a well-researched rap-style poem about newspaper apologies displays the same level of attention to detail. Repeating the mantra “Sorry we said” to a cheeky jazz tune, Peppiatt treats us to a litany of false allegations – ranging from the most serious (“Sorry we said you stuffed your dead child in the boot of a car”) to the most inane (“Sorry we said you can’t afford a settee”) in a powerful commentary about press inaccuracy and cruelty.

Among the most unlikely people to be queuing for a ticket at Edinburgh’s Pleasance Theatre are former News of the World chief reporter Neville Thurlbeck, Daily Mail Editor Paul Dacre, Mail Online Editor Martin Clarke, former Sun Editor Kelvin Mackenzie and Express Editor Hugh Whittow.

The one hour and 20 minute monologue is structured around video footage – both home-made and supplied by the disgruntled – in which Peppiatt confronts each man for flawed thinking and hypocrisy with a mercilessness he must have learned on the Star.

The totems of Fleet Street are ruthlessly toppled in scenes which had the audience (which counted Hugh Grant and Max Mosley among it) in fits of disbelieving laughter. The Daily Star may claim to have “more balls than The Sun” but Peppiatt’s are huge.

On the recurring theme of spherical objects, the show ends unforgettably with close-up hidden camera footage of Thurlbeck’s naked nether regions as he receives a full body massage at the naturist Dorset guesthouse he stayed at ‘in the call of duty’ – but evidently enjoyed somewhat beyond it. Don’t eat beforehand as Thurlbeck’s meat and two veg are not a pretty sight – unless of course you are the guesthouse’s owners Sue and Bob Firth who secretly filmed him in the event that scores should ever need to be settled. If ever Thurlbeck rued one of his own headlines it will now forever be: “The Guesthouse where All Rooms Come with Ensuite Pervert”. And if anyone doubted the rumours that he seriously enjoyed his stay – or missed the internet footage – this one’s for you. Mrs Thurlbeck, please stay away.

Other hilarious footage shows Peppiatt’s delivery of a dildo to the doorstep of Paul Dacre’s home in a private Kensington mews. In a desperate bid to get “the man determined to keep the nation in the missionary position” to loosen up about sex, and in retort to Dacre’s sanctimonious condemnation of Max Mosley, Peppiatt battles with a burly security guard to deposit sex toys and debate the rights and wrongs of door-stepping, arguing: “Mr Dacre will understand. He has had a 30 year career in the press. I’m not invading his privacy and I’ve got a gift receipt”. With true tabloid determination to drive home his disrespect for the Mail’s “cock and bull moral philosophy” he then drives to Derry Street and projects an energetic porn film onto the exterior of Northcliffe House.

It’s also come-uppance time for Mail Online editor Martin Clarke when Peppiatt’s candid camera catches him stumbling home from the shops in unflattering baggy shorts, shirt and sandals and sporting a “belly button slit”. ‘Take that’ for your nasty side bar of shame, ‘take that’ for your bitchy shots of celebs looking awful. In a poke at the worst kinds of tabloid invasiveness, Peppiatt takes special care to film the door number of Clarke’s house, naughtily reassuring him: “Don’t worry, we’ll blank it out” (which he doesn’t).

But it’s not all daft and titillating as serious points are made. For example Peppiatt zeros in on the Express editor’s evidence to Leveson in which he blamed the lack of intervention by the PCC for his newspaper’s crucifixion of the McCanns. This kind of absurd excuse-making is ridiculed in a videoed stunt in which Peppiatt papers Whittow’s car with the worst of the front pages. Then, when the editor returns from walking his dog and starts to rip them off, Peppiatt rebukes him for not turning up earlier to stop him.

In a high quality imitation of Ali-G style spoofing, our erstwhile reporter also dyes his hair grey, gives himself a silly name and blags an interview with Kelvin MacKenzie for a non-existent Canadian broadcaster called Grabbola Productions in which he gives the ‘smug albino bull-frog’ three editorial scenarios and asks if he would publish them. After robustly answering “yes” to the first two, the unsuspecting publisher of “Gotcha” and “Up Yours Delors” is suddenly a little less inclined to the affirmative when presented with some titillating extra-marital text messages of his own and the penny finally drops.

Back on stage, in comparison to these memorable video vignettes and other carefully compiled material, some of the gags – such as jokes about Muslims ‘taking over’ – just don’t seem funny. The novelty of this kind of ‘shock stand-up’ (pioneered by Asian comedian Shazia Mirza years ago) has now been done to death and doesn’t need to be resorted to. Similarly some sections (such as where Peppiatt compares both his career and the concept of privacy to a broken hymen) seem a bit tortured and beckon the delete button for the final cut.

Peppiatt is excellent when doggedly ridiculing nonsensical tabloid ‘stories’ and berating journalists who conduct ‘an orchestra of inanity’. He singles out a ridiculous piece from the Mail Online where literary language is deployed to describe a ‘bikini malfunction’, tearing it to shreds with visible gusto. This is someone who seriously respects language, whose reading ranges from Homer and Voltaire to Orwell and ‘the last text box of the first ever Spiderman cartoon’, and he doesn’t want it messed with.

Let’s hope that after the curtain comes down in Edinburgh the on-line comments about Mr Peppiatt’s first show won’t be anything like the ones he so lovingly picked out for Kelvin MacKenzie. Just one thing Richard: tuck in your boxers – the side bar of shame is still up and running.

Preview at Theatre 503, 503 Battersea Park Road, London, Monday 16 June 2012

Athalie Matthews is a media law associate at Bindmans LLP and the Inforrm Reviews editor.