From his perspective as an outsider, a homosexual writing in 1960, Tennessee Williams shines a forensic light on suburban marriage in the southern states in 1953. The results are often hilarious. Who would think to look in the Williams’ oeuvre for a Christmas comedy? The discovery of this one, as sweet as a peanut butter-and-jelly sandwich - albeit with a helping of iron filings on the side - is most welcome.

Newly-married Isabel Haverstick is deposited on the doorstep of Ralph Bates’ compact little home in Nashville on a snowy Christmas Eve. Could there be a more fairytale all-American setting? A glowing fire, a Christmas tree and Bing Crosby singing “Have Yourself a Merry Little Christmas” on the television have not so far cheered Ralph, however. Still, he’s ready to welcome his old army chum George and his new bride. Unfortunately, George drives off without Isabel and, oh dear, Ralph’s wife has just left too. And besides, the sweet little house has a great fissure in its wall and occasionally rocks as if succumbing to an earthquake because, as Ralph frequently reminds us, the house is built over a cavern and will eventually tumble into it.

This neon-lit metaphor - the times, Williams is signalling, are a-changing - could, like the play itself, lead to caricature. It is to the credit of director Howard Davies and his cast that, broad though the humour sometimes is, the characters’ predicament remains touching. Before long, all four are in the house, working out their salvation, their version of the post-war American dream.

The two young men have been buddies in the Korean War and are ill-prepared for picket-fence propriety. Their wives, meanwhile, are prepared for nothing else. Ralph and George know far more about male camaraderie than women’s needs, family life or even, it turns out, sex. George, possibly a virgin after a failed wedding night and despite his apparent bravado with Korean call-girls, is suffering from “the shakes”, a kind of palsy which expresses his psychological anxiety about love-making. Ralph, who fears his son is being turned into a sissy, complains about his wife’s sexual demands.

There is a great gulf between the sexes which echoes the contradictions in American culture: free in post-war peace, but plunged into Cold War paranoia; striving towards equality, but aspiring to family perfection which has more to do with Disney than real human experience.

Lisa Dillon, with her Marilyn Monroe wig and Dolly Parton consonants, triumphs as Isabel, even when announcing: “The world’s a big hospital and I’m a student nurse in it.” The hard-won you-all drawls are sometimes a distraction otherwise, but each of the actors - Jared Harris as Ralph, Benedict Cumberbatch as George and Sandy McDade as Dorothea, wife of Ralph and daughter of his ex-boss - manage to mix compassion with broad-brush satire.

The characters are (as we are frequently reminded) undergoing a period of adjustment just as America was at the time. But then, that period never ends for any of us.

- Heather Neill