WHEN the latest series of New Tricks first hit our screens, some fans may have been wondering if it was going to be the last.

With Alun Armstrong and Amanda Redman both following in the footsteps of James Bolam and stepping down from the crime drama, just how long could it continue?

Well, the good news is that the tenth series has suggested there’s still plenty of life in the old dog yet.

New recruits Sasha Miller (Tamzin Outhwaite) and Danny Griffin (Nicholas Lyndhurst) have fitted straight into the Ucos team, while Armstrong and Redman’s exit episodes have left some more excitable fans wondering if there could even be scope for a couple of spin-offs.

After all, what lover of quirky comedy dramas wouldn’t want to watch an eccentric retired couple searching for missing persons in Brian and Esther Investigate?

And surely TV is well overdue a series about a feisty detective who hunts war criminals with the help of a ghostly sidekick in Pullman and Halford (Deceased)?

But while those series remain pipe dreams, what has made New Tricks so seemingly indestructible? Well, it seems the stars are as stumped as the rest of us.

“When I joined, I asked the other cast members why the show was so huge. They had no idea,” says Denis Lawson, who was the new boy before Lyndhurst and Outhwaite arrived.

“Some say it is because young people are too busy watching online or on iPad or playing computer games. But the show is a hit in universities and its fastest growing audience is in its 30s. It’s huge overseas – Dennis Waterman has heard from people in Indiana and the Middle East, and I get big hellos from Australians over here.

It’s bafflingly huge.”

There’s another mystery to ponder in tonight’s episode – the last in the current run – as the team takes another look at the case of notorious crime boss Edward Monroe, who was convicted of the murder of prominent oncologist Alistair Caldwell.

The Met officer who handled the original case, DCI “Headline” Hennessy, has been accused of suppressing evidence, and Strickland wants to know if Monroe could have grounds to appeal.

But the case presents Miller with a dilemma – she believes Monroe was mixed up in the murder of former CID partner Josh Tyler, who was working undercover in the crime boss’ gang. So, when a discovery seems to suggest Hennessy mishandled the case, will she speak up or keep quiet in the hope of getting the result she actually wants?