Who can resist one of Degas’ women? Bathing, dancing or stretching, their soft curves are captured so tenderly that it’s disappointing when you learn that the man who rendered them was a misogynistic celibate. And then you come across Suzanne Valadon, arguably the love of Degas’ life, and one of the greatest female artists of the 20th century.

Valadon is almost entirely unknown in the UK, but she is to get a long overdue introduction in Timberlake Wertenbaker’s latest play, a three-hander at the Arcola, starring Henry Goodman as Degas.

The story begins in late 1880s Paris, where Degas, aged 54 and amusingly crotchety, is already a master painter. He is worshipped by the artists of Montmartre, despite having alienated many of them with blistering criticism and open anti-Semitism. Believing that a true artist’s private life must be sacrificed for his work, Degas lives alone, except for his housekeeper, Zoe Cloziers (Selina Cadell).

Enter a sexy, brash young women in an extravagant hat, striding into Degas’ studio demanding he look at her drawings. She’s hypnotically beautiful but Degas is used to resisting the ladies. Disgusted by her association with Toulouse-Lautrec, for whom she is currently modelling, he is not interested — until he sees her work.

Valadon is played at the Arcola by Sarah Smart, who herself went to art college before she began acting. “She was amazing,” Smart says. “She was really naturally gifted and really ahead of her time; her drawings and paintings are just fantastic, some of them really provocative. I’d never heard of her, but when I saw her work, I was like, why haven’t I?”

Born to an unmarried laundress in Montmartre, Valadon grew up in relative poverty, but drew obsessively as a child. “She joined the circus for a little while,” Smart says, “but she hurt herself so she was knocking about with all the artists and became a model.” Valadon’s long list of lovers makes for some serious name-dropping. Before modelling for Toulouse-Lautrec she was associated with Renoir and Pierre Puvis de Chavannes, and later a Spanish painter, Miguel Utrillo, who fathered her son, the better-known artist Maurice Utrillo.

Goodman, sitting beside Smart during a break from rehearsals, makes the comparison with Tracey Emin. “There is an issue about how women artists survive in a male culture,” he says. “Valadon was this sort of modern, at-ease-with-herself woman, who, if she wants to screw somebody, screws somebody.”

Valadon did achieve huge success, especially for her outrageously candid nudes and vibrant colour. She had four retrospectives in her lifetime, and when she died in 1938, Picasso, Braque and Derain were among those who attended her funeral.

But highlighting Valadon’s work was not Wertenbaker’s aim. Since her big break, Our Country’s Good, in 1998, her writing has explored everything from the contemporary art world to Charles Darwin. “I think Valadon’s work is remarkable and it should be better known,” Wertenbaker says, “but that’s my judgment, and it wasn’t the purpose of the play. It was an attempt to describe these three people as objectively as possible.”

The play explores the tension between Degas’ traditional, stringent discipline and Valadon’s wild, young rejection of it; his celibacy versus her sexuality — all under the watchful eye of Clozier, whose relationship with Degas is almost that of a wife. “I was terribly intrigued by them, particularly Degas’ generosity towards Valadon,” Wertenbaker adds. “It’s not part of his reputation and it showed great love.”

Goodman says he now looks at Degas pictures with new eyes. “It’s that inability to show expression, and yet desperately wanting to show truth and sensitivity and delicacy. More widely, what the play does is expose us to a situation where artists are painting in a suit and tie, selling their work to the Americans, buying new clothes — and yet hating the Americans, hating the shops. It’s about the cost of trying to remint who you are against the pressures of the period that you’re living in.”

Goodman points out, too, that such pressures still exist, highlighted by the play’s location in East London. “Three hundred yards away there’s a tailor, all day long sitting in the window sewing. There are decent low-income families living in mutual support against the materialism of metropolitan London. Staging it here adds another sense of the cultural pressures that exist within the play,” he says. “If the cognoscenti want to see it, they have to come and see it here in East London.”

The Line is at the Arcola Theatre (020-7503 1646, arcolatheatre.com ), Nov 18 to Dec 12

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