The Twits, Royal Court, review: Roald Dahl's spiteful couple fail to charm in this padded-out production

Enda Walsh's production re-imagines them as a pair of disgusting Toffs

Jason Watkins (Mr Twit) and Monica Dolan (Mrs Twit)

With the lucrative successes of Matilda the Musical and Charlie and the Chocolate Factory still going strong in the West End, you might have thought that jumping on the Roald Dahl bandwagon was a relatively risk-free exercise for a theatre. The Royal Court's new stage version of his 1980 book, The Twits, has the dubious distinction of being the first show to destroy that illusion.

It seemed, in theory, to be a sure thing. Who better than Irish dramatist Enda Walsh, with his antic flair for communicating the darkly warped and confined, to adapt Dahl's tale of a revolting, spiteful couple who thrive on playing stupid, sadistic pranks against each other?

It's certainly a witty idea to posh the Twits up as a pair of disgusting toffs. Jason Watkins, ridiculously grandiose, paunchy, and filthy-bearded, and Monica Dolan, all mad-haired, fanged malice in a Barbour, ooze the misanthropy and uncouth sense of entitlement of the upper-class yob and execute the vindictive knockabout with unholy verve.

But Dahl's original is a short work and here the practical jokes with the glass-eye, the worm spaghetti, and the surreptitiously extended cane et al seem to be dispatched in about fifteen minutes leaving over an hour-and-a-half to fill before the couple get their sticky, inverted come-uppance.

So Walsh extends our heroes' CV of nastiness by introducing three Yorkshire folk who are tricked into staying with them in the vain of hope of having their stolen fairground returned. The Twits delight in brazenly reminding their guests of how they were duped out of their livelihood. They force them to watch inset plays in which their pet monkeys, the Muggle-Wumps, perform scripted re-enactments of their humiliation.

It's as if “The Mousetrap” in Hamlet were to have been devised by the dastardly Claudius and presented as a staggered trilogy of plays. This emphasis on back story, though, is wordy, unwieldy and confusing for a young audience who have to get the hang of monkey-impersonations of crucial, not especially easy-to-follow events in the past. John Tiffany's production works hard to keep the distinctions crisp and comic but you're still often left with doubts about who this show (officially recommended for age 8-plus) in being aimed at.

Oliver Llewellyn-Jenkins (Monkey Son) and Glyn Pritchard (Monkey Dad)

Chloe Lamford's impressive design – with the Twits' decaying cylindrical house giving way to woodland and the visitors' caravan, a vehicle that inevitably triggers memories of Jerusalem on this same stage – creates the right creepy mood. But despite some enjoyably bad-taste sequences (a Christmas dinner with Rudolph the red-nosed reindeer as the piece de resistance), the proceedings feel padded-out and lacking in the requisite energy and reprehensible glee. And though the fairground folk tug the odd heart-string (especially Dwane Walcott as the stammering Handsome Walzer Boy), there's no winning, bullied child-protagonist to root for here, unlike in Matilda and Charlie.

I sat there fantasising about an alternative scenario in which, to diversify their cruelties, the child-phobic Twits sign up with an adoption agency...

To May 31; 020 7565 5000