Shetland review: Douglas Henshall shines as TV's most northerly regional detective

Everything about Shetland (BBC1) is so well-judged that it seems unfair to pick on one performance in particular. I have to, though: Douglas Henshall. Now in his fifth series as DI Jimmy Perez, Britain’s most northerly regional TV detective, Henshall seems almost weathered into the part, as if, like the hills and cairns around the windswept isles he serves, his mournful visage has been lashed by the North Sea for millennia.

There is something about the undemonstrative, thoughtful, dreich Perez personality that is so naturalistically captured by Henshall. Apart from an unhealthy obsession with his late wife, we see little of whatever emotional action might be going on underneath that grey-blond barnet. Maybe there isn’t any. Even when his “ardent” possible-girlfriend Alice (played with appropriate frustration by Catherine Walker), starts making drunken gibes about his emotional hangups, Perez maintains preternatural control.

Ageless as Henshall seems, in fact it was only in 2013 that the BBC broadcast the first dramatisation based on Ann Cleeves’ novels, and the subsequent productions have proved as popular as the Scandi-noir series they so often mirror.

Which means that the storylines are often as lowering as the skies, and few bleaker than the current one about kidnap, exploitation and people trafficking.

Such is the globalised nature of that line of business that the gangsters, and their victims, even end up in such unlikely vicinities as Shetland. In this mystery we start with the severed remains of an arm, fingerprints burned off, being washed up on a beach. When it is discovered that the limb belongs to a young Nigerian man, and that there is a certain amount of contact between him and some of the dodgier islanders, the lazy assumption is that it is another outcrop of the drugs trade. That turns out to be quite wrong; and as we learn more about the dead boy we discover that the reason he is in Shetland is to try to rescue his sister (Titana Muthui, superbly bewildered) from those holding her captive for a ransom.

His mother Olivia (Rakie Ayola, excellent) arrives in Shetland to recover her son’s remains and save her daughter. Perez now realises that what he is facing is much more than a few cannabis farms, and is far, far bigger. His view of Olivia turns from suspicion to compassion, and the squalid, terrifying predicament the family find themselves in might soften the heart of even the most militantly anti-refugee Ukipper. You’d hope.

Perez finds out who is behind the trafficking – a pure evil Glasgow thug by the name of Paul Kiernan (John Kazek). But we’re still left, alongside Perez, with the task of finding him and, more to the point, solving the subsequent murder of the Hayes, a local couple who made an immodest living from immoral earnings. There are links between trafficker Kiernan, the Hayes and hardup trawlerman Calum Dunwoody (Ryan Fletcher) who rents his boat for the purposes of transporting migrants, but we are yet to work out precisely how they are related, and implicated.

Like all the best detective dramas, Shetland engages the audience in the very process of detection. That way we grow intrigued, and we care. And so we find ourselves sitting next to Henshall in his (prominently featured) Volvo V70 estate, sharing his thoughts, intercepting suspects and being driven off the road by unidentified enemies. We are with him in his hopes, we are proud of his fundamental decency, we too enjoy the odd drink with friends, witnesses and colleagues, including the equally prosaic-but-brilliant DS Alison “Tosh” McIntosh (Alison O’Donnell). The one thing we do that Perez never seems to is to wonder at the homicide rate. For Shetland is a place where the body count currently exceeds the number of detectives available to solve the cases. A mystery best left unsolved, probably.