“Rafta, rafta” is the Hindi for “slowly, slowly,” suggesting that married love is something that grows and deepens with the years. It is a good translation for the title of Bill Naughton’s All in Good Time, the 1963 northern domestic comedy on which Ayub Khan-Din has based his exuberant and highly enjoyable new play.

It is over ten years since Khan-Din produced East Is East as a collaboration between Tamasha, the Royal Court and the Birmingham Rep, so Nicholas Hytner’s production is a welcome boost to the cause of British Asian comedy. The outline is the same as in Naughton: a young married couple have trouble consummating their union in the crowded terraced house belonging to the groom’s parents. Their bed collapses. “If there’s anything you need,” suggests Dad most unhelpfully, “just tap on the wall.”

Tim Hatley’s design, a two-tiered, opened-out doll’s house arrangement of kitchen, living room and two upper bedrooms, is revealed behind a photographic gauze of a Lancastrian terraced row of houses. Bill Naughton’s Bolton has moved with the times, and the play’s opening post-wedding party is a riotous procession of garlanded guests and a steaming vat of curry. “There are people starving in India,” someone shouts at the extravagance of it all. But the line only provokes more laughter.

Preserving Naughton’s three-act structure, the conflict between generations and much of his no-nonsense northern bluster (“Never refuse a man point blank,” says mother-in-law, “or he’ll take it out of your house-keeping money”), Khan-Din has pasted over a new thematic coating about immigration and new values. Eeshwar Dutt, the paterfamilias whom Harish Patel plays with such beguiling charm and brilliant comic timing, has worked for 28 years in the factory but still remembers the look people gave him when he first arrived. His wedding present was a water buffalo, whereas his son’s wife is flaunting a new Blackberry.

The crisis of non-consummation is caused by domestic proximity and complicated by anxiety and parental expectation. This leads to questions of potency and even sexual ambiguity, climaxing (if that is the right word) in the remarkable scene of old wounds and deep feelings between the two sets of parents. The comedy is finally – triumphantly - resolved with coupling.

In some ways, the Asian treatment works even better than did the Young Vic’s glorious reclamation of Hobson's Choice some years ago, but that show is the template for re-casting northern comedy. And Hytner’s recent deployment of Yorkshire Asians in the arranged marriage plot of The Man of Mode has clearly extended the cultural possibilities of updating the classics.

Harish Patel, one of nature’s obvious Bottoms with his wobbly head, exquisite gestures and bountiful good nature, is partnered by an impressive and slyly humane Meera Syal as his wife. The young couple are beautifully played by Ronny Jhutti and Rokhsaneh Ghawam-Shahidi. Atul works in the local cinema, a lowly job that releases an ironic seam of reference to Bollywood and aspirations of moving up in the world. The play is full of such felicitous new suggestions and, if the first night audience is anything to go by, the NT will succeed in shifting its demographic composition yet again in an important new direction, that of the middle-class professional Asian community.

- Michael Coveney