Emma Thompson is at her best in Ian McEwan adaptation The Children Act

Thompson is finding new shades of scepticism and warmth nearly 30 years on from her first cinema role.

The Children Act, published in 2014, has a clever title, slippery in a way that is characteristic of its author, Ian McEwan. Like the double meaning in Enduring Love, it can be read two ways. It refers to the UK’s 1989 Children Act which decrees that the court must safeguard the child’s welfare, but it poses also an implicit question. What could it mean, this idea that the children act?

The answer comes when the book introduces 17-year-old Adam, who has leukaemia and will die unless he receives the blood transfusion recommended by his doctors. Adam is a Jehovah’s Witness, and it is up to Fiona Maye, a judge in the Family Division of the High Court, to decide whether to overrule his parents and church by insisting that the procedure go ahead. In an unorthodox move, she visits him in hospital before making her decision: “It occurred to her that this intellectually precocious young fellow was simply bored, under-stimulated, and that by threatening his own life he had set in motion a fascinating drama in which he starred in every scene…” There we have it: children act.

Adam is celebrated in the early parts of the novel but, like Hickey in The Iceman Cometh, his arrival is tantalisingly delayed; it is not until almost halfway through that Fiona first sees him picked out by “the focused bright light around the bed.” Richard Eyre’s film version is scripted by McEwan himself (the fourth instance of self-adaptation in his career, after On Chesil Beach, The Innocent and a 1984 TV film of his short story Last Day of Summer) and Adam’s entrance is especially well-staged, preceded by a couple of teasing shots in which his face is hidden from view. When Fiona walks in, he is sitting bolt upright in bed. “Brilliant!” he cheers, as though the leading lady in his play has finally arrived. (Adhering needlessly to protocol, he even calls her “My Lady”.)

Adam’s exclamation cannot be extended to the film as a whole. This isn’t cinema so much as Sunday evening television, with a moral dilemma laid out in straight-arrow scenes stripped of much cinematic sensibility, give or take Dan Farrell’s impressively clipped editing. But it does feature two performances which justify the use of the bigger medium. Fionn Whitehead (the gaunt young greenhorn from Dunkirk) has an impressive command of gesture as Adam, whose theatrical, adolescent romanticism is inseparable from his religious fervour. Though it’s a pity that the evocatively pretentious poems with which he expressed himself in the novel have been replaced by a bedside duet with Fiona of “Down by the Salley Gardens”, Whitehead’s conviction is still intensely persuasive. At one point he even appears to be channelling Damien from The Omen, and briefly it seems possible that someone is about to have their eyes pecked out by a raven.

Fiona is played with gentle and progressively crumbling authority by Emma Thompson, who is finding new shades of scepticism and warmth nearly 30 years on from her first cinema role in the Richard Curtis-scripted comedy The Tall Guy. “Not suffering fools gladly since 1989,” could be Thompson’s motto, but in The Children Act, as in all her best work, it is the touches of uncertainty amid the righteousness that unlock the soul of the character – as emotion begins to threaten Fiona’s resolve, and her own childlessness influences her judgement, Thompson captures the interior panic of a woman losing her bearings. Her restless, unfaithful husband Jack (Stanley Tucci) delivers some explanatory dialogue (“You’re the big authority on family matters and yet when it comes to your own, you’re like a sulky child”), but we can get everything we need and more from Thompson’s little intakes of breath or the tilt of her head.

The film’s commercial chances are better than those of the recent and superior Apostasy, which presented a complex portrait of Jehovah’s Witnesses from the inside and didn’t have star power to sweeten the pill. The Children Act isn’t challenging or upsetting, as that film was. Fiona may go through turmoil as the inadequacies are exposed in her comfortable life of tennis doubles and first-class travel, but audiences can observe it all from a safe and untroubled distance.

The Children Act (12A)
dir: Richard Eyre