Amongst Friends, Hampstead Theatre, London

Funny word, "amongst". It hath an unnecessary archaic ring, methinks, whilst also suggesting something stilted in the offing, or perhaps the offertory. And so it proves, with playwright April De Angelis bringing old neighbours to dinner with a high rise couple, a journalist and her MP-turned-novelist husband, to study the fissures in their friendship.

But de Angelis is also invoking a social comedy of 20 years ago, Michael Wall's Amongst Barbarians, which recounts a true story of English drugs smugglers facing the rope in the former colony of Penang, Malaysia.

Here, Lara and Richard's guests are a nurse and a drugs counsellor, Joe and Caitlin, who represent the ongoing but overrun care-in-the-community function that operates beyond these walls. The high-flyers have fenced themselves in from the world

How will these old friends be jolted back into a shared consciousness, or even onto common ground? The ritual of the dinner party is transformed by the arrival of an uninvited guest, ostensibly delivering the food but also delivering a jeremiad of guilt, sorrow and accusation that embroils all four in the fate of an allegorical young man.

So far so very J B Priestley, but the application of this theatrical principle is spoilt by the confusion over the dead boy's identity until we give up worrying about it and accept it merely as a trigger: the guest is a raucous specimen of the working class, Shelley (Vicki Pepperdine), who has slipped the attentions of the bosses and the carers, equally.

It's a good idea that the script never fully charges with dramatic life, relying too easily on the flabby shock effect of four-letter words and the surprise development of a body overboard.

But Helen Baxendale and Aden Gillett are suitably self-satisfied as the charmed couple, she armour-plated in her designer cocktail dress with vividly irresponsible opinions, he gormless with delight in his richly deserved success with suddenly imported memories of fiddles on expenses. As an ex-MP, he is held responsible for inadequately equipping the troops in Iraq, while Lara banged the battle drum in her columns.

The drugs counsellor has let everyone down, too, though that doesn't stop him sneering acidly from the sidelines, something James Dreyfus does extremely well, while his soul mother partner, Caitlin, played with effusive warmth by Emma Cunniffe, is sucked back into her affair with the guilt-free Richard. Shelley implicates them all, but can't force them to sign cheques for the youth centre she's trying to build in honour of her son.

Caitlin has already written a self-help book on breasts, and by the end of the play is turning towards the poisoned fungus of kiss-and-tell, while Lara is hovering like a kite to tear her apart. Anthony Clark's production is suddenly suffused with black despair, but it's too little too late.

To 13 June (020-7722 9301)