3.5/5 stars An actress of Emma Thompson’s calibre is rarely given a lead role worthy of her talents. In The Children Act , based on the novel by Ian McEwan, the Oscar-winning actress pounces on the rare opportunity, delivering a terrific portrayal of a High Court Justice whose dedication to her career threatens to ruin her marriage. You Were Never Really Here review: Joaquin Phoenix in masterful hitman thriller As Judge Fiona Maye, Thompson is called upon to make a ruling in the case of a 17-year-old leukaemia patient – regarded as a minor by the courts – who is refusing a blood transfusion because of his religious beliefs as a Jehovah’s Witness . Maye visits the boy, Adam (Fionn Whitehead, Dunkirk ), in hospital and is struck by his intelligence, artistic passion and his religious devotion. Adam insists that a blood transfusion is “wrong, because we know it’s wrong”, a philosophy that draws comparisons with Maye’s home life. Her husband Jack (Stanley Tucci), who is in a state of desperate frustration, has announced his intention to start an affair with a younger colleague. He claims to still love his wife, but says that her work has caused them to drift apart. Early on in the film, Maye states that her court is one “of laws, not morals”, yet almost immediately Richard Eyre’s film sees her question her own statement. How can she know what is best for Adam, a lucid and clearly competent young man, when she doesn’t even know what is best for herself? This self-doubt sparks a crisis of conscience in Maye that threatens her entire livelihood. McEwan’s weighty subject matter is countered skilfully by gentle humour, embodied best by Maye’s long-suffering clerk, played with unflappable charm by Jason Watkins. Even when the script paints itself into a couple of corners in the third act that can only be escaped through slightly unbelievable, melodramatic plot twists the impeccable performances ultimately steer The Children Act to a compelling climax. The Children Act opens on September 13 Want more articles like this? Follow SCMP Film on Facebook