BBC Juliet Stevenson ‘I spent hours hanging upside down to film Wolf’s hostage scenes’

If you loved Sherlock and Inside Man and like sleeping with one eye open, then the BBC’s dark new crime thriller Wolf might be your next TV treat.

Based on the horror novel by Mo Hayder, Wolf has an all-star cast from Ukweli Roach and Juliet Stevenson, to Game of Thrones stars Owen Teale and Iwan Rheon

But Juliet – who plays middle-class hostage Matilda Anchor-Ferrers – admits filming the terrifying horror left her unable to relax in her own home without checking all her cupboards for lucking baddies.

“I love thrillers,” confesses Juliet. “But they’ve got to be really good and this is a really edge of seat thriller. "

"I’m quite sophisticated in guessing where something might go," says Juliet. "Or where the criminals are lurking. But with this one, it’s constantly surprising with both stories.”

Juliet’s character Matilda spends much of the series tied up which tapped into her childhood fears. “And as someone who from early childhood was terrified about people breaking into the house it was weird to end up playing that out,” says Juliet. “I’m in a flat in New York now and I come in every night and check every cupboard in the apartment, to make sure nobody’s here.”

The six-part drama has two narratives, the first sees Ukweli’s character DI Jack Caffrey obsessing over his neighbour who he believes murdered his 10 year-old brother in the 90s. Meanwhile, the wealthy Anchor-Ferrers family find themselves at the mercy of two psychopaths. When the two stories collide, it leads to a disturbing race against time.

“Jack is reluctantly drawn into solving this mystery,” says Ukweli. “He has to do it in order to get answers for his brother. So although it starts off with reluctance, I think his Wolf-like qualities are that once he picks up the scent that there is actually something to be solved and there’s a real mystery, he starts to run with that.”

Meanwhile, in Monmouth, Oliver, Matilda and their daughter, Lucia Anchor-Ferrers return to their isolated house. Their home just happens to be very near to where a set of murders took place five years earlier – a case which Jack investigated. Soon, the family are held against their will by sadistic psychos Honey and Molina.

“Honey is a complete psychopath,” explains Sacha Dahwan who plays him. “He holds the family hostage for a mysterious reason. You’d think it would be for money, but it’s not. But unfortunately, for Honey, he’s been lumped with the worst sidekick ever.”

Honey and Molina (played by Iwan), are let into the house under false pretences and the family quickly realise they’ve made a big mistake as the pair show their true, terrifying colours.

“Owen and I spent weeks and weeks tied up,” explains Juliet, 66. “I sat handcuffed to a radiator and that was a very strange experience to be rendered so powerless.”

“It was horrific,” agrees Owen. “Because it is our job to believe it and wonder what it would be like for two people to be brought into your home and then do these things to you.”

Juliet’s scenes were physically difficult – because she was hung upside down.

“The most difficult thing is when Matilda’s hanging upside down for long stretches of time,” reveals Juliet. “I had to train on a machine to acclimatise to having my head full of blood, it was physically quite challenging.”

As the two narratives don’t collide until near the end of the series, the cast were split and hadn’t seen the other actors at work until it was all put together in the edit.

“I didn’t get to film with Owen or Juliet or Sacha,” says Ukweli. “So I was really excited to see that story. I read the script, but I wanted to see what they did with it. And I’d heard from the crew how great they were, but I didn’t get to witness any of it, so to see it – I can confirm, they’re all so amazing.”

“It was a great day,” agrees Juliet. “It was great to see Ukweli give such a fantastic performance. It was weird for Owen and me because we filmed on separate days so we never saw the other half of the story, it’s so layered and rich and detailed.”

Game of Thrones stars Owen and Iwan worked closely together in the series, but surprisingly it was the first time they’d shared the same screen.

“People put Iwan and I in the same camp a lot of the time because we were inveterate b*****ds who bring about a bit of drama,” laughs Owen. “When I was sent the script for this, I could see Iwan was going to be playing Molina as well and I remember thinking ‘oh it’s odd on that my character’s going to turn out to be a psycho as well, isn’t he?’ I can see where this is going!"

“I’ve got a lot of love for Iwan,” adds Owen. “I was bowled over by his and Sacha’s ability to maintain credibility while being totally absurd. It’s intriguing that life, at its most pathetic and moving, can also have an absurd sense of comedy.”

Wolf starts Monday 31st July July, 9pm, BBC One