Two Doors Down: What's the secret of the sitcom where nothing happens?

Two Doors Down is the Scottish sitcom which has been quietly creeping into living rooms across the UK for a decade.

And it's an ordinary living room where the show is set. Latimer Crescent is home to Beth and Eric (Arabella Weir and Alex Norton) to Christine (Elaine C Smith) and to Colin (Jonathan Watson) and the show revolves around them and the various friends and neighbours who find reasons to intrude into their home.

The show has been networked from the start, but this, the seventh series, will move to BBC One.

"It's always had a loyal following," says Kieran Hodgson who plays Gordon, the partner of Beth and Eric's son, Ian (Jamie Quinn).

"But each year, it's got bigger and bigger. And now BBC One which feels very well deserved."

Fans of the show include Graham Norton, Peter Capaldi, Zoe Ball and David Tennant.

"I think it works because there's a great level of universality," Kieran says.

"Yes, it's set in Paisley and a lot of the time the conversation seems to be around very Scottish things but it has a grounding in reality which allows you to really believe in these people and their lives.

"And these lives are being led across the country, and those micro aggressions are being experienced in living rooms from Lerwick to Truro."

The show has had a slow but steady rise. Creators Simon Carlyle and Gregor Sharp created the original pilot in 2013 but it was another three years before a series was commissioned.

Characters have come and gone over the years, and fans will be delighted to see the return of Cathy, the monstrous but glorious wife of Colin, played by Jonathan Watson.

"Don't get me wrong," Jonathan says. "I've enjoyed working with Siobhan Redmond [who plays new girlfriend Anne Marie] and I've enjoyed Colin's adventures on Tinder but having Doon Mackichan back as Cathy has been great."

"If Eric and Beth anchor the programme, Colin and Cathy bring chaos as soon as they enter the room."

And don't assume that the programme revolves around any major happenings. The genius of TDD is that nothing happens. Think The Royle Family. Or a swearier version of The Broons.

Kieran Hodgson agrees: "It all revolves around small trivial incidents that then take on rich and obscene life.

"There's one episode where all that happens, is that Alan (Graham "Grado" Stevely) has some spare doughnuts.

"That's the thing. If you keep the stakes low, there's no end to small events that you can dramatise and explore."

But the success of Two Doors Down has been tinged with sadness. In August, just weeks after filming on the series finished, Simon Carlyle died. He was 48.

"It's still quite difficult to come to terms with, to be honest," Jonathan says.

"We had the press launch the week before last in London. We showed a couple of episodes, and it was really odd because he should've been there.

"He'll certainly be in our thoughts when we sit down to watch the new season."

Kieran agrees, and says the show serves as a tribute to his talent.

"But reaching this pinnacle is doubly, triply sad for us all," he says.

"The delight and pride we have watching these latest episodes is tinged with huge sadness because we were working on them together, just a couple of weeks before he died.

"We've lost a friend first and foremost and someone taken away far, far too young, but we've also lost this wonderful project that he and Gregor created and that we all came to love."

Two Doors Down is on BBC One on Friday at 21:30 and BBC Scotland on Sunday at 22:30.