Under a Blue Sky, Duke of York's Theatre, London

'A' for effort, but Catherine Tate fails to pass test

A sudden crash of rumbling, terrifying noise. A retina-assaulting rectangle of blue, jangling light. In a neat Ikea kitchen, the explosion of the Canary Wharf bomb is heard by Nick (Chris O'Dowd) and Helen (Lisa Dillon). But they don't want to talk about that. Nick and Helen, both teachers at the same state school in east London, have something far more important to discuss – their long-term non-affair. Helen loves Nick, and Nick loves being loved by her. There, if he's honest, his interest ends.

There, if I'm honest, mine ends too. But there are two more couples to meet, Graham and Michelle, and Anne and Robert. All four are also teachers, linked to Helen and Nick through their various placements at various schools, and none of them any more able to have a straightforward relationship than the first hapless pair.

The six adults who populate David Eldridge's play all behave like adolescents. Because of their shared profession, there is presumably a tacit invitation to surmise that their work may have something to do with this. Are they unable to commit to each other because they are so committed to their vocations? Do they simply spend so much time with teenagers that they are unable to move beyond the limitations of puberty themselves?

Back in the day, when teachers still commanded the respect that they need to do their work, an enduring cliché was of the ageing and single pedagogue, married only to his or her classroom. Perhaps Eldridge's message is that in the present time, with teaching more demanding and less satisfying, it is much harder to gain solace from nurturing the children of others. Perhaps not. The audience can only speculate. Little in Eldridge's banal and workmanlike script gives a clue to any wider psychological pressure that teachers, singularly, may face when conducting the business of separating their working lives from their private lives.

There are references to the well-documented and troubling difficulties that the profession faces. Nick has decided to teach at an independent school, because he is fed up with concentrating on "crowd-control" and fancies having a go at teaching English to a group of young people of whom more than half speak the lingo as a first language. Helen is appalled by his decision, seeing working in the public sector as a glorious and romantic act of moral martyrdom that only the spoiled and shallow reject.

All this perfectly recognisable observation, though, is mere backdrop. The staging of this play may rely on few props – a kitchen unit, a table, a bed. But the stage is cluttered with great chunks of spoken lumber, plonked down around the place, haphazard and unanchored, neither divorced from the action, nor central to it.

Not that there is much in the way of action, or interaction. The formal staging of the play is crushingly simple also – three two-handers, of half-an-hour each. They are competently described sketches of messed up human relationships, but nothing more.

The most comic and pathetic pairing is that of Graham and Michelle, an inadequate and unattractive pair played with heavy-handed humour by Catherine Tate and Dominic Rowan. The most touching and warm pairing is of Anne and Robert, played by Francesca Annis and Nigel Lindsay. But even here the script is laughably familiar. Annis is even obliged to deliver a long meditation on her Auntie May, whose young love died on (who'd have imagined) Flanders Field.

The reference is to Jean Brodie, but Muriel Spark did it all many years ago, and so very much more brilliantly, that Eldridge's nod is nothing less than a self-immolating insult. This is an awesomely middlebrow, schematic and undemanding piece of work.