Playing Nice is beautifully done – but they miscalculated the opening scene

There must have been a time when slow-burn psychological thrillers didn’t start with a scene of high drama followed by a caption that reads ‘Three months earlier’ – but if so, it’s getting hard to remember it. The latest programme to deploy the tactic was Playing Nice, which began with James Norton running towards the sea screaming ‘Theo!’ as a child’s body bobbed, face-down, in the waves. He was next seen, post-caption, laughing with his pre-school son in various picturesque Cornish locations while using the word ‘buddy’ a lot. Not to be outdone in the great-parent stakes, his wife also piled on the cuddles for little Theo.

Before long, Miles had developed the habit of glowering menacingly when nobody was watching

This idyll, however, didn’t last long. The couple – now identified as Pete and Maddy (Niamh Algar) – were summoned to the local hospital and told that, owing to an unfortunate mix-up, they’d been given the wrong baby three years earlier. Their biological son, it transpired, was David, whose equally misled parents, Miles and Lucy (James McArdle and Jessica Brown Findlay), lived in a spectacular clifftop house straight out of Grand Designs.

After an emergency summit, it looked as if the two parties had come to a civilised agreement: each couple would keep the child they’d bonded with, but also become part of the other’s life. This idyll, however, didn’t last long either. As Pete and Maddy continued to live up to the programme’s title, we began to realise that Miles might not be the good-natured charmer we’d originally taken him for.

At first, this was signalled only by a tendency to perhaps overdo the smiling. But before long, he’d developed the habit of glowering menacingly when nobody was watching. By the end of the first episode, he’d served Pete and Maddy with court papers demanding custody of both children.