After the Dance, NT Lyttelton, London<br/>Love Story, Minerva, Chichester<br/>The Fantasticks, Duchess, London

Drawing-room dramas were once written off as hopelessly passé, full of stuffy or merely silly toffs. British theatre's revolution – famously begun by John Osborne in 1956 – gave the nobs the boot. Terence Rattigan was, instantly, yesterday's man.

Yet his best plays have slowly edged back into favour, exploring suppressed griefs beneath a surface gaiety. In his long-forgotten tragicomedy from 1939, After the Dance – now revived by the National – a river of quiet despair runs under the hedonistic frivolities played out in the Scott-Fowlers' plush Mayfair flat – all silver-green silk, with a darkening sky over the parapet balcony.

David (Benedict Cumberbatch) and his elegant wife Joan (Nancy Carroll) lounge around, pouring themselves snifters and laughing at the flippant quips of their freeloading pal John (Adrian Scarborough). With their dizzy youth far behind them, they still throw wild parties, the booze now taking its toll, and the crisis of the Second World War looming.

David's cash-strapped cousin (John Heffernan) and his girlfriend, Helen (Faye Castelow), are also hanging around the flat, although, as assertively serious-minded twentysomethings, they are teased for being bores. But Helen is covertly hooked on David, and offers him the chance of a fresh start. Perhaps Thea Sharrock's ensemble needs a fraction more fine-tuning and Castelow's high-pitched, cut-glass voice is tiresome, while her comical-going-on-stunning insensitivity would register fully with more pauses. One might wonder, also, if Cumberbatch shouldn't show a few more vulnerable chinks in his armour of suavity.

The play's big emotional revelation comes as a dramatic jolt, as played here (which seems to be a directoral choice: Sharrock could have chosen to drop hints). On the whole, though, the layered complexity of Rattigan's characters is intriguingly handled. Cumberbatch is electric when he's fuming, yet maintains a debonair pose, cigarette aloft. Carroll, in her turn, becomes achingly poignant, privately devastated by events, though her husband is oblivious.

Scarborough is also superb, lolling on the sofa like a fat, dopey Labrador, but razor-sharp when he finally rips into David. Pandora Colin's cameo, as the boho gossip Julia, is hilariously flamboyant, and bruising as well.

This is definitely worth catching and, if you want more, 2011 is the centenary of Rattigan's birth with a BFI retrospective and celebratory productions at Chichester Festival. In the meantime, I could have done without Chichester's Love Story, Erich Segal's slushy tearjerker, adapted from the bestselling novel and Hollywood film into a new chamber musical.

Though Segal wrote the book in 1969, his student sweethearts – Oliver and Jenny – are hardly in tune with the hippie hedonism of the time. Oliver (Michael Xavier) is a preppy Harvard student, while Jenny (Emma Williams) is a scholarship girl and budding concert pianist. Of course, they can't resist each other, yet both contrive to keep their smalls on (even under the sheets) in Rachel Kavanaugh's production. Fair enough, Chichester is blue-rinse, not blue-movie terrain.

What's mind-numbingly corny is the narrative. Stripped down by adaptor and lyricist Stephen Clark, the couple's whirlwind romance is a risibly schematic rushed job. Boy meets girl, they fall into bed and – before you can say "Jeepers!" – he has proposed and it's meet-the-parents (irked on his side, accepting on hers). Then it's the wedding, the move up the property ladder, the plan to have babies, blah, blah.

OK, Love Story was never going to be my cup of tea, not with a ton of sugar poured into the mix. At the same time, though, it leaves a faintly sour taste. In the effort to keep the running time to under two hours, Xavier's Oliver is made peculiarly unattractive by the lack of explanatory background for his pater-loathing vitriol. That he might feel guilty about Jenny ditching her career to be a stay-at-home wife is, likewise, brushed aside in a few lines.

For all that, it is their marriage's very mundanity that makes the sudden tragedy of Jenny's leukaemia hit home. It's hard to remain dry-eyed at the end. Peter Polycarpou manages to be touching and charming as Jenny's adoring Italian-American pop. Kavanaugh makes Clark's fast-forwarding visually fluid. And with a string quintet and grand piano in a white arc upstage, Howard Goodall's score rises above the dialogue, offering rippling, playful sprees of melody, and some haunting ones, too.

Finally, a few words about the West End's latest American musical import, The Fantasticks. Well, gee, you guys, this is unbelievable garbage! Just how this scrappy clown show, which would barely amuse a six-year-old with its muddle of vaudeville, Pyramus and Thisbe and Hispanic bandits – has managed to run for a half-century in New York is a major mystery. Even with Clive Rowe, Paul Hunter and Edward Petherbridge aboard in London – all with twinkle-toed comic timing – I'd be amazed if this lasts the summer.

'After the Dance' (020-7452 3000) to 11 Aug; 'Love Story' (01243 781312) to 25 Jun; 'The Fantasticks' (0844 4124659) to 4 Sep

Next Week:

Kate Bassett will be viewing Through a Glass Darkly, the Almeida's new Ingmar Bergman adaptation