When Lewis stars Kevin Whately and Laurence Fox announced they were taking a year out from the show, rumours started flying – fuelled by the actors themselves – that instead of a sabbatical it could be the end.
It was a gloomy prospect for Lewis fans who found comfort in the show following the demise of the original Inspector Morse series.
But back at the start of last year there was a glimmer of hope in the form of a pilot show called Endeavour.
It marked the 25th anniversary of the first Morse episode and told the story of Morse as a young detective in the 1960s who was secretive about his first name, Endeavour.
The pilot was a huge hit, scoring exceptional viewing figures. As a result, more than a year later, Endeavour is returning to our screens for a four-episode series.
The stars of the new show – Shaun Evans, who plays Endeavour Morse, and Roger Allam, who takes the role of his mentor, Detective Inspector Fred Thursday – are in a light-hearted mood as they explain how they created their on-screen relationship.
Asked if they took part in bonding exercises, they giggle like a pair of naughty schoolboys and Shaun quips: "Oh yeah, there was that one in the sauna."
Roger chips in: "And there's the dancing exercise. It's nice to see panic in the director's eyes when we say we like to do the scene first as expressive dance."
Taking up the theme, Shaun continues: "It's quite a sight to behold. Hopefully it will be on the DVD extras. Do you like dance?"
They are joking, of course, but once talk of Morse the Musical has come to an end ("Morse, Morse, Morse! I like it," says Shaun), the pair switch to serious conversation, discussing how they prepared to take on such a beloved British institution.
"I had never watched the show," Shaun admits. He focused instead on reading the books, aware that an impersonation of John Thaw, the original Inspector Morse, was the last thing that was wanted.
"When I first got the job I very specifically said that it had to move forward. I said if they want someone to do an impression of anything that's gone before they should look elsewhere. But it seemed we all wanted the same thing," explains the 33-year-old Liverpudlian actor.
That's why, while Endeavour might reference old Morse and his penchant for cryptic crosswords, classical music and a pint of ale, the character actually feels novel and fresh.
And if Shaun had his way, Endeavour would be a little seedier than Morse. "He's got a fascination with porn in the books, I'm always fighting for that," he says.
Each episode of the new series is filmed by a different director. While some actors might have found such diversity challenging, Shaun and Roger agree it was a positive.
"It made it exciting," says Shaun. "There's no room for complacency, each came in and tried to better the latter. It's a great atmosphere to work in."
Roger was more familiar with Morse than his co-star. He appeared on the other side of the law in one of the original Morse episodes.
With such a successful pilot, it seems a no-brainer that the show will win a big audience. But after 13 years of Inspector Morse and seven series of Lewis, there's always the risk that TV viewers might have Morse fatigue. Shaun and Roger don't seem concerned, however.
"There's a big hunger for something that straddles Sunday evening," says Roger. "Something that's an exciting, interesting and well put together, feature-length."
Shaun agrees, but says ratings weren't on his mind during filming. "If you come to work desperate to please or seeking a massive audience, it will never work," he says. "If the work is of a high enough quality then my hope is that it gets an audience. That's all you can wish for really."
Neither actor is interested in the show running for as long as Inspector Morse. "With those long American TV contracts you think, 'yes, at the end of that I'd be rich'," says Roger. "But at the same time you feel inside you a kind of death, because I enjoy playing lots of different characters."
All of the scripts were passed by Colin Dexter, author of the original Inspector Morse novels, before filming.
"I don't think it's a contract thing, it's a courtesy thing," says Shaun. "It's right because the nucleus of the characters came from him – no one else knows them as well."
If you watch closely you might spot Colin Dexter in the background – he features as an extra in each episode.
And if you've got a particularly good eye for faces, you might also spot John Thaw's daughter, Abigail Thaw, who plays the Oxford Mail editor.
And of course this wouldn't be a real Morse show without the traditional Oxford setting. "It's a beautiful place," says Shaun, "but also with the architecture and the people that populate it, it all clicks into place, it's such a specific part of these stories."
But with Oxford being a small city, it's hard for a large film crew to go unnoticed.
While Shaun managed to avoid recognition, Roger was approached by several fans of The Thick Of It, in which he played grumpy, sarcastic MP Peter Mannion.
Followers of the political satire show will be sad to hear that as far as Roger is aware, it really is over. "I think they've shot it in the head," he says. "I keep trying to start a campaign to get it resuscitated. They might do the odd special. I hope they leave room for that."
If Roger can get his loyal following to back his campaign, it might have some clout. It's pointed out that he has an excellent and very dedicated fan site. "So there should be," says Shaun.
Endeavour begins tomorrow on ITV1 at 8pm.