CARDINAL'S Billy Campbell has revealed why the ‘tensest ever’ season four had to be the last.
The 60-year-old actor plays the titular John Cardinal in the drama, which returned for its fourth and final season tonight on BBC Two.
The series is adapted from the Giles Blunt books, which are set in the small fictional city of Algonquin Bay, in Northern Ontario, Canada.
While Billy says the new series is "our most tense season", he also explained why it had to be the last.
Speaking to the Toronto Sun, he said: "We’re working with Giles’ books and we’ve already cannibalized all six of them.
"So nobody really wants to go off the map as far as that’s concerned.
"Nobody wants to go out in the wilderness without the maps that Giles’ books have provided us because bad things might begin to happen.”
But if Giles wrote more books, Billy would return to the role, no question.
He said: "That could work. It would work for me. It’s been the best role of my career and the one that I was most well-suited for.”
Fans are desperate to see what crime Cardinal and his partner Lise Delorme (Karine Vanasse) are going to solve, and if the detectives finally get it together after witnessing their true feelings simmering below the surface.
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Speaking about their relationship, Billy told the Toronto Sun: "This season, that feeling that has been unspoken between Cardinal and Delorme no longer has an obstacle — that being Cardinal’s wife.
"The two of them are able to really for the first time comprehend this thing that’s between them.
"If you’ve appreciated the growing feelings between Cardinal and Delorme so far, it’s a satisfying season. You’ll be happy with how that’s resolved."
Cardinal continues on Wednesday, June 10 at 9pm on BBC Two.