24 Hours in Police Custody, Channel 4

“Your law is too soft. Make it more strict.” An Albanian illegal immigrant suspected of handling stolen goods was unimpressed by the courtesy extended to him by Bedfordshire Police. Too many pleases and thank yous, he complained. In Tirana the rozzers probably don’t ask you if you have any food allergies.

The thin blue line has launched Operation Charm Offensive. In September Channel 4 broadcast Cops and Robbers about how police in the West Midlands deal with serial petty offenders, and they came over as secular saints. Next year there’s a big BBC One series inside the Met, who are presumably keen to repair their reputation for flogging stories to the tabloids, failing to investigate phone hacking, kettling and the like.

There’s been nothing so vulgar as docusoap-style foregrounding of so-called characters

And then there is 24 Hours in Police Custody, the seventh and last episode of which was shown on Channel 4 last night. It’s hard to tell whether the policemen and women in the series have been minding their Ps and Qs with 80 cameras trained on them, but they have come across as remarkably tolerant and humane people performing a difficult job to an exceptionally high standard without ever, apparently, losing either their rag or their marbles. When an Albanian illegal immigrant says he doesn't like spinach, they don't give him spinach.

That’s not to say the audience has been fed blandishments and bromides. Previously in Luton nick, we’ve had conspiracy to murder, drug dealing, honour-based violence and paedophilia to go with regulation domestic disputes and drunk and disorderly behaviour. The series has taken as its narrative structure the time constraint imposed on police from the moment a suspect enters a cell. They have 24 hours in which to gather enough evidence to make a charge or they must let the suspect go. Although it’s not the police’s job to keep us entertained with weekly rushes of adrenalin, that’s what has happened.

There’s been nothing so vulgar or opportunistic as docusoap-style foregrounding of so-called characters, but some seemed more naturally fitted to appearing on screen than others. But appearances are deceptive. In last week's outstanding episode, "Honour Thy Father", DC Rachel Chandler (pictured right) seemed happy to present herself a ditzy flapper. But when she compellingly interviewed a Pakistani man accused of assaulting his daughter you forgot all about the floral print dress and the lip gloss. The suspect, we later learned, was jailed for three years. And then there have been the fascinating array of suspects, angry, nervous, compliant or plain not bothered, some with their faces obscured and, in the case of one suspected paedophile, their voice encoded too, but others freely filmed.

"The Crime of the Century" - the title came from a theft of 98p's worth of Diet Coke - was one of the quieter instalments. A massage parlour was raided, though no proof could be found that anyone was running the place as a brothel. The Albanian was deported. But the series has reflected the reality of policing, that not all the work is nail-biting. This final film turned into a gentle press release about the police as equal opportunities employers as Sgt Wil Taylor, investigating the brothel case, was revealed to be a double amputee. His moving story became the focus of the episode. The message didn’t need underlining, but the police care about their own as much as they care about the rest of us.

The series as a whole has shown our multifarious society at its most knackered and dysfunctional, and the all but impossible job of cleaning up the mess. The result has been not only gripping but also enlightening, and of course profoundly depressing. It questions the need for anyone to watch crime drama with all its synthetic additives, the junk-food cliffhangers and addictive twists that keep us all carefully hooked. There’s nothing so dramatic as the real thing.