Lawyer Emma Averill has it all – a good job, a loving husband, two kids – but as her 40th birthday approaches, her life starts to fall apart.

I have a history with Insomnia. Not the not-getting-to-sleep bit (that’s a pain when it happens) but Sarah Pinborough’s story. First thing on the morning after my heart attack I messaged her saying it looked as if I had a long stretch of bed rest ahead, and was there any chance of an ARC? She kindly arranged it and Emma’s tale was my companion for the next few days.

Jump forward two and a half years to now when I’m very much editing rather than writing for SFB and Insomnia reappears as a Paramount+ series, starring Vicky McClure as Emma. There’s no question of my not covering it and the publicists kindly arrange screeners before I talk with Sarah (an edited version of which can be read here). I restrict myself to one episode a day; although I suspect it will work well as a binge watch, I think the decision to drop episodes weekly is a good one, as the tension mounts and each episode ends with a strong cliffhanger.

If you’ve read the book you have an idea of what’s coming, but Sarah and her team have made many changes, from the obvious – it’s no longer a first-person story, so there’s a chance to flesh out many more of the characters with additional plotlines – to the less so (the case with which Emma is involved is gender-flipped, which adds a further level of tension). Coming to it unspoiled, you’ll get caught up in Emma’s life, in all its many facets, as things start to go haywire.

The casting is superb across the board – McClure and Leanne Best are totally believable as siblings, with Tom Cullen’s Robert key throughout (there’s a scene involving an iPad that’s simply brilliant), while the families and friends gel in a way that makes you believe we’re just popping in on the lives of ordinary people.

Börkur Sigthorsson’s direction completely sells the disorientation of the sleepwalking sequences, as well as the incomprehension displayed in the flashbacks. The ratcheting up of the tension begins with the first scenes but there are enough moments where the story is allowed to breathe and there’s sufficient doubt sown constantly that you are never quite sure if your faith in some of the characters is justified – McClure in particular allows Emma to be unsympathetic at times, and you totally understand Robert’s anger and decisions.

Verdict: A gripping tale that increasingly exerts its hold on you – and I suspect, like me, by the later episodes you’ll be shouting at the screen! 9/10

Paul Simpson

Insomnia is available on Paramount+UK now, with new episodes every Thursday.