This harrowing drama is about a parent’s darkest fear – the disappearance of their child.

It follows children’s author Stephen (Benedict Cumberbatch) as he and his wife Julie try to come to terms with the loss of their four-year-old daughter Kate.

Based on a novel by Ian McEwan – whose books also inspired the films Atonement and Enduring Love – it sees him attempt to piece his life back together and rekindle his relationship with Julie.

Stephen can't stop looking for his daughter (
Image:
BBC)

Father-of-two Benedict understands the horror of the situation.

‘There was a point where I said to the director, “I’m worried I’m getting too upset in too many of these scenes”,’ he says.

‘It’s hard to avoid. It was very intense, emotionally and psychologically, to play. The situation is harrowing for anyone to imagine, but it’s unthinkable for a parent.’

Despite the heavy subject matter, his co-star Kelly Macdonald, who plays Julie, believes the one-off, 90-minute special is ultimately uplifting.

‘Although this horrendous thing has happened, the drama is really about love,’ she says. ‘It’s an emotional drama but it’s not depressing. You see the human spirit in it, they are real and human and they still have humour and hope.’

Stephen and Julia face an unbearable situation (
Image:
BBC)

Hope keeps the couple afloat, and they are sure Kate is alive somewhere. In one heart-wrenching scene Stephen even follows a little girl into school, believing he’s found her at last. As he struggles to come to terms with his grief, he works on a government committee on childcare.

But strange questions begin to arise. Why does the Prime Minister (Elliot Levey) want to see him? And why has his friend, junior minister Charles Darke (Stephen Campbell Moore), become a recluse, playing odd soldier games in the woods?

The role is very different to Benedict’s recent turn as comic book hero Doctor Strange in the Hollywood film.

‘I wanted to portray someone closer to me,’ he says. ‘Someone who didn’t require hours in hair and make-up. It was quite nerve-wracking because I’ve not done that for a while. I even wore my own clothes.’

The stars’ excruciatingly realistic depictions of suffering make the drama a must-see. Harrowing as The Child in Time is, at its heart it’s a story of a couple’s enduring love for their daughter – and each other.

The Child in Time is on Sun 9pm BBC1