New Tricks, BBC One

Moving the action to an exotic location is usually a sign of desperation when a character-based drama is flagging on home turf. New Tricks, most at ease in Soho and Stepney, hobbled into its tenth series with a two-parter set in Gibraltar – which is what passes for an exotic location in a show whose idea of the big chase is a sprint through the botanical gardens.

Alun Armstrong, supremely glum (as well he might be, for he has seen the script) and grounded by his boss, DS Sandra Pullman (Amanda Redman, pictured below) and the high-ups, slipped the leash to join his ageing cops from the Met’s unsolved crimes unit in the Med. Banged up in a shipping crate for no clear purpose, he must have felt more keenly than his character Brian Lane that the end is nigh.

Armstrong and Redman are leaving the programme, following in the footsteps of James Bolam, whose Jack Halford went to die in France. At the outset theirs was a winning team, even Dennis Waterman’s sleazy Gerry Standing getting away with his ladies’ man act. Ten years on, we view elderly peacocks with more suspicion. Denis Lawson’s ill-defined turn as no-nonsense Scot Steve McAndrew has proved no substitute for Bolam’s steely compassion, and plots are often either dull or tortuous. The current crop of old dogs and their minder, landed with this tourist board promotion, did their best with a yarn about the apparently unrelated deaths of a man and a boy, with Redman fetchingly boarding a yacht to drink white wine and Armstrong (pictured below) cleaning up in a casino.

Rotten luck for all, then, that in the week between episodes one and two, Gibraltar should fly into the headlines as the place where concrete blocks are thrown into the harbour and tolls are slapped on crossings into Spain. All that promotion gone for nothing.

More interesting, and clearly setting up his exit, is the subplot that was supposed to take geeky Brian Lane out of this investigation. He has assaulted a sleazeball officer whose negligence over the death of a black teenager in custody, and subsequent cover-up, have not impeded his way to the top. New Tricks knows its audience – still healthily around the eight million mark: the sort of people who correct apostrophes on public signage and know there are two "l"s in marvellous. It’s perfectly fitting, then, that the proof of collusion hinges on a spelling mistake. Michael Gove will probably put New Tricks, whose idea of banter is a riff on Moby Dick, on the national curriculum.

But Brian and Sandra are exchanging lines about policing not being a job but a life, Sandra is welling up a lot (which is usually a sign that she's thinking about her disgraced police dad), Brian is rueing his estrangement from son Mark, and the inestimable Susan Jameson as his wife is laying down ultimatums. Sandra invariably falls for the villain; maybe an unsuitable fling is on the cards. Redman is shortly to be replaced by Tamzin Outhwaite.

Also looking out his V-neck sweaters is Nicholas Lyndhurst. That will leave Waterman as the only original member of UCOS. Let’s hope that Antony Calf, the Teflon deputy chief commissioner, stays the course: his masterclass in survival and urbanity grows more compelling with every year. What will remain of New Tricks is five characters in search of an author. All applications to the BBC: no age limit.