ALL good things must come to an end – and sadly, we may be saying goodbye to DI Robbie Lewis at the conclusion of this series. It’s not the first time he’s left our screens, of course – the first was when Inspector Morse ended, but the signs are he’ll be going for good this time, so make the most of three new cases with sidekick Hathaway.

Last summer Laurence Fox, who plays Hathaway, let slip in an interview that both he and Kevin Whately – who’s played Lewis since the first Inspector Morse drama in 1986 – had decided to move on to new things. However, ITV are yet to confirm this is true.

Whately certainly thinks his alter ego is beginning to slow down. “Lewis is starting to feel his age and he knows he’s getting near police retirement,” says the actor.

“He’s feeling the distance between his family, who are based in the North. At the same time he’s aware Hathaway is considering his future, a subject that comes up in a couple of the films in different ways.”

Whately recognises that much of the show’s success is down to its largely unsung hero – Oxford, where the drama is set.

“The nature of the city and the university attracts people from all over the world to work there, particularly academics,” he explains.

“It’s quite a competitive place. I was reading recently about a court case where one of the dons was found dead in suspicious circumstances and he’d been strangled by another don. When I read about the murder I thought, ‘There’s a job for Lewis’.”

It will be back on screen later in the year too when Endeavour, the prequel to Inspector Morse, returns to our screens.

But for now, we’re concentrating on Lewis and Hathaway, who begin with the murder of Reuben Beatty, a research fellow at the University of Oxford’s psychology department.

He had been leading a double life as a supposed psychic, which his colleague Vicki Walmsley claims was part of an experiment into the psychology of faith.

She also believes that Reuben may have been killed by his mentor, Andrew Crane, in an effort to keep him quiet about a series of military experiments he had been working on.

Meetings with more local psychics throw the entire case wide open, and then there’s a suggestion Reuben was killed in an act of euthanasia. But who by, and why?

Sanjeev Bhaskar guest stars.