Helen McCrory is one of our most fearsome screen faces, having followed up her stints as one of the Malfoy clan in the Harry Potter films and a witch-demon in Penny Dreadful with a chilling portrayal of sister Polly in the BBC’s Peaky Blinders. However, as Hester Collyer in The Deep Blue Sea, the only person in danger from her is herself; the play opens with the discovery of Hester unconscious in front of an unlit gas fire after a failed suicide attempt.

The 1952 play is often regarded as Terence Rattigan’s masterpiece. Even though it’s set in a Ladbroke Grove rooming-house, it remains inescapably middle-class; Rattigan couldn’t make the landlady sound much more plausible than Noël Coward could with the tea-room staff in Brief Encounter. But it’s admirably sensitive about the issues it touches upon.

In one case this is almost a by-product. Rattigan is sympathetic towards the then-crime of attempted suicide, though this is at least partly because it’s standing in for that of homosexuality: he wrote the play in the wake of his own gay ex-lover’s suicide. Hester’s mortal discontent, though, is due to unhappiness first in her marriage to a high-flying lawyer, now a judge, and then in deserting him to live with a high-flying, er, test pilot, now nothing much except a former test pilot, golf hustler and alcoholic. Both of these men treat her as an accessory of one kind or another, someone whose satisfaction and worth derive from the man she’s attached to.

This attitude may explain why the play appealed to director Carrie Cracknell, whose recent successes include the anti-sexist dance-theatre piece Blurred Lines, also at the National Theatre, and her searing version of A Doll’s House, which went from the Young Vic to the West End and then Broadway. It also enables McCrory to engage in the kind of understated, buttoned-up acting that shows how much more dignified and restrained Hester can be than these men, even in the midst of confusion about her own life. The likes of you or I couldn’t have got through some of these exchanges without biting our lip clean through, but McCrory manages at once not to say things and yet to show what’s not being said and how much the not-saying is costing her.

Nick Fletcher also excels as the one man who does understand Hester, a German-born doctor now struck off for unspecified shady practices. As Freddie the fly-boy, Tom Burke skilfully combines hunkiness of look with an unattractively selfish manner. There’s a rash of Rattigans around at the moment, for no obvious reason (his centenary was five years ago), but this is the best I’ve seen.

Written for The Lady.