The People Next Door (Channel 4 )

KARL Davies is best-known for playing Robert Sugden in Emmerdale, but he has turned to the thought-provoking one-off drama The People Next Door to raise important questions about surveillance and interfering in the lives of others.

Directed by Ben Chanan, the man behind Cyberbully, Blackout and The Missing, we look at the lives of young expectant parents Richard (Davies) and Gemma (Joanna Horton), who move into a new home and soon hear disturbing sounds through the wall – arguments, screams, and what sounds like violence soon become daily intrusions, and they suspect a child is being mistreated.

With little help on offer from the authorities, the couple turn detectives in a bid to uncover what's happening behind closed doors. But are they worse than the neighbours from hell and invading the privacy of others?

"What drew me were the blurred lines of who's right and who's wrong, and it raises some important questions. I think it highlights the difficulties the authorities have because of the red tape and hoops they've got to jump through, and how far people should go. Hopefully, it sparks a lot of conversation," says Davies.

iPhones, handheld cameras and a variety of different devices were used by Davies and Horton to shoot the project with, hopefully, few put off by the term “found footage”.

"I thought it was going to be a really quick process, but it took a while because everything we filmed had to get reviewed, and then we'd get performance notes and script notes and camera notes. I underestimated what was involved."

Davies has never received any formal training, learning on the job instead.

He was eight when he took part in his first school play but admits that despite enjoying it, he "went off to play sports". In 2000, he was cast in Emmerdale and scored a ratings winner over four years playing Robert and struggling in a relationship with adoptive brother Andy. He's since appeared in Dolphins, The Case and The Syndicate, and joined the ranks of those who can boast about playing a role in mega-successful Game Of Thrones.

"It was like being on a blockbuster movie," says Davies, who played Alton Lannister in series two. "There would be campsites and guys on horseback and fire pits all over this valley, and you'd just go, 'Wow'. It was an incredible spectacle."

His favourite job to date is the Norfolk-based Kingdom, "which I did three series of with Stephen Fry – it was an absolute dream". "He's one of my heroes, who is perfectly fine to meet, because he won't disappoint. He just got his mates to appear, so every episode I'd be working with comedy royalty, which was so much fun, and in a beautiful part of the world."

He now has two movies in the can – Fractured, which he also co-produced, and The Dark Channel – and he's currently shooting the 1980s-set Brief Encounters, in Sheffield, about a group of women and risque Ann Summers parties.

Grantchester (ITV, 9pm)

WHEN Sidney's old friend Reverend Sam Milburn visits the parish claiming to be seeking forgiveness for his crimes, the vicar is torn. Matters complicate further when Harding Redmond finds out he has returned and makes threats against his life, and Sam flees. With his friend now missing, Sidney fears the worst and must once again join forces with Geordie to investigate. Meanwhile, Leonard continues to wrestle with his feelings for Daniel Marlowe, and a visit from Mrs Maguire leads to Amanda having a heart-to-heart with Guy. Last in the series.

Secret Britain (BBC1, 9pm)

THE team heads south to Kent, and yes, those White Cliffs of Dover will be featured, although Denise Lewis gets an unusual view of them – while abseiling down their face in search of a rare plant. As the Olympian dangles in mid-air, Ellie Harrison keeps her feet firmly on the ground by heading to Kent's furthest outpost. Chris Hollins, meanwhile, could end up knee-deep in goodness knows what while exploring the marshes located in the north of the county.

Viv Hardwick