This is a deliciously closely-observed play about infidelity, both the venturous and the vengeful kinds, hilariously funny while being moving without sentimentality. Middle-aged Tom (Sean Campion) has just confessed to an opportunistic liaison with a woman he met in a pub and his wife, Joan (Niamh Cusack) is full of scorn which reveals that their marriage has become so familiar it seems propped up with mutual loathing. Peter (Matthew Lewis, or Neville Longbottom if you’re under 25) is a young male prostitute in a precarious relationship with checkout girl Tara (Ruta Gedmintas). Both couples’ lives become entwined with each other’s various deceits, no one left blameless, yet none without some excuse for what they have done – or claimed to have done.

Much of the delight comes from McCafferty’s superb dialogue and the exquisite comic timing of the excellent cast. There is a particular speech where Tom encapsulates his sense of alienation and futility in the existential torture of having to choose a sandwich, which is both acutely observed and brilliantly funny. Elsewhere, at Joan’s insistence, Tom gives a graphic account of precisely what happened in his squalid doorway knee-trembler, and its explicitness is entirely at home in a play which is fundamentally about the sex act and its consequences. Though young, Peter is incapable of satisfying Tara without the need for Viagra, because of the demands of his day job. Though beautiful, Tara needs to prove her desirability by offering herself to Tom. Though vengeful, what Joan ultimately wants is to forgive.

Set changes are effected by a slow overlap of personnel, a device used increasingly, though the principle piece of furniture, a large double bed, was significant perhaps mostly for the extent to which it did not get used. Some scenes weren’t convincingly representative of say, the hotel bar, largely because of its presence.

These quibbles need to be set aside, however. This is an extremely engaging and funny piece of theatre, and should be seen in the intimacy of this curious pop-up space in Charing Cross Road.

Paul Caira

Unfaithful plays at Found 111 until October 8th and performances begin at 7.45.