It’s as if you turned up to Centre Court and found yourself watching a ping-pong match. Richard Bean has made his name as a heavy slugger, painting on large canvases, cracking broad jokes. One Man, Two Guvnors filled the National with unprecedented guffaws. England People Very Nice filled it with almost unprecedented outrage, when the play was reviled (wrongly) for advocating the racism it depicted.
The Mentalists is a different beast. First seen 13 years ago on a small stage at the National, this two-hander never moves out of a B&B in north London’s Finsbury Park. It could, of course, be bounded in a nutshell and contain infinite space. Actually, it’s a desultory affair, haunted by interesting ideas.
It is not surprising that Abbey Wright’s production is already pulling in audiences. Stephen Merchant of The Office and Steffan Rhodri of Gavin & Stacey star. This is canny as well as popular casting. Bean’s play has something in common with The Office: the meander from joshing to bullying, baleful aspiration, self-deception.
Merchant comes on as an innocuous middle manager, using the spindly gangle of his limbs and his wurzel accent to appear ineffectual. After all, has anyone (other than the former defence correspondent of the BBC Mark Laity) ever had a West Country burr and been taken seriously on stage or screen? In fact, he has a plan for putting the world to rights that has sinister aspects. His old friend (Rhodri), a beaming, slightly preening coiffeur (“Keep your hair on!” he exhorts in a crisis) is with him to make what looks like a porn video but is in fact Merchant’s message to initiates.
The two are easy together on stage, batting about some fairly funny lines – “The Greeks? They peaked early.” Richard Kent’s design conjures up the B&B all too vividly: grimy plugs, orange chairs, a picture of very shiny horses, telly perched like a surveillance camera. Drawing on two of his previous existences, as social psychologist and standup, Bean comes up with an incisive encapsulation of behaviourism, the theory that animates his antihero. Forget Freudianism: after all, if you are sitting next to a stranger on a bus, you don’t care about what he is thinking: “It’s what he’s doing with his hands that makes you nervous.”
This should be a lively argument in the theatre, where you can watch gesture and intention struggling for supremacy. Not here. A plywood banter drowns everything out, even an interesting contradiction between the behaviourist tract and the father-fixated characters: Rhodri has a lovely time inventing a dad who is a champ boxer and creator of the miniskirt. It is a whimsical excursion with stars. Not derailed, just drifting.
• The Mentalists is at the Wyndham’s until 26 September
