The Line, Arcola Theatre, London

An art history that lays it on too thick

The most recent play in which Timberlake Wertenbaker regards art from a feminist perspective, The Line, deals with the relationship of Degas and his protégée, Suzanne Valadon. Despite its claim to a new look at the past, however, dramatically the play is stiff and stuffy. If an earnest, provincial art school decided to put on an end-of-term entertainment, this would be just the ticket.

Indeed, the first lines of the play are set in familiar territory. It's the discovery-of-importunate-young-genius bit, with a gruff watchdog of a housekeeper brushing off Valadon, a model who wants to show Degas her drawings. The great man appears, and also tries to shoo Valadon away, but finally looks at her work and is astounded by its brilliance. The second half opens with an even more blatant, and risible, cliché – the housekeeper, reading the paper to Degas, says brightly, "Here's an article by Emile Zola."

If the content of this drama takes us back to many other plays (or Hollywood film bios), the construction takes us nowhere at all. The Line contrasts Degas, the austere, celibate, and classically educated son of a well-to-do family, who saw himself as carrying the torch of Ingres and Delacroix, with Valadon, the promiscuous daughter of a drunken cleaner and an unknown father. At 23, the girl, who has never had any art lessons, becomes Degas' pupil, but chafes at his insistence that she respect and study the work of the past and see her own work in relation to it. Valadon makes a passionate outburst, defending her right to paint what she wants, in the way she wants. A bit later she makes another such outburst. Later still she makes a third one. But she says much the same thing each time. "I'm going to do everything I want and I want to paint now," she announces in one scene. Three years later she is defying Degas once more: "I'm going to make great big canvases full of colour, and maybe they won't be Degas but they'll be Valadons. They'll be new and shocking and me!" For all the squawking – and for all Degas' insistence that a work of art must have movement – the play keeps plodding in place.

As well as the conflict between immediacy and tradition, Wertenbaker considers the competing claims of art and life. Degas insists that Valadon devote herself solely to her work, as he has done to his, for it is impossible, he says, to be married and to be a great artist. In fact, the haughty, acerbic Degas was never known to have had any relations with women (the critic Robert Hughes thinks he may have been impotent), so his bachelor state is not quite the great renunciation that he makes out. In the final scene Valadon and the dying Degas have a meeting ("I would have done anything for you"; "I'm going to die without having tasted happiness") straight out of soap-operetta. Wertenbaker also softens Degas' anti-semitism (it was an open sore 20 years before Zola enraged him with J'Accuse) and presents him as his own worst victim.

Matthew Lloyd's production accentuates the educational-theatre note by hanging the theatre's walls with reproductions of Degas' work. Henry Goodman gives this one-and-a-half-note character no more than the required severity and pathos, but Selina Cadell makes a dignified and touching figure, with a touch of welcome drollery, as the protective housekeeper. Though we are meant to sympathise with Valadon, Sarah Smart makes it difficult, with her shrill charmlessness, even to listen to her. The Line may please those who like an occasional evening of high-minded boredom, but – as so many plays at the Arcola alone have demonstrated – theatre can fulfill, and deserves, much higher expectations.

To 12 December (020 7503 1646)