The real AC-12: discover the police anti-corruption officers who inspired Line of Duty

Veteran crime reporter Duncan Campbell investigates a history of bent coppers – and the officers tasked with catching them


This was first published in March 2017. Line of Duty season one will be repeated on BBC One from 3rd August at 9pm. 


A violent abduction in plain sight. An unsolved murder. A missing woman. In the new series of Line of Duty, the police are under pressure to catch the culprit and the senior investigating officer, Detective Chief Inspector Roz Huntley – played by series newcomer Thandie Newton – is feeling the heat from her superiors. But is someone tampering with the evidence? Is there a dark plot within the police force itself to frame an innocent man?

This fourth series of Line of Duty kicks off at the same high tempo to which its many loyal admirers are now accustomed, and there will be no shortage, over the next six weeks, of what series creator Jed Mercurio describes as “diabolical twists”. Set in a fictional police force – the first series was shot in Birmingham, the subsequent three in Belfast – it follows the activities of AC-12, a small anti-corruption unit. Since it first arrived on BBC2 in 2012, Line of Duty has swiftly established itself as one of the finest of police procedurals, earning it a promotion this time around to BBC1.

The three leading members of AC-12 – Superintendent Ted Hastings (Adrian Dunbar) and his sparky sergeants Steve Arnott (Martin Compston) and Kate Fleming (Vicky McClure) – are investigating allegations against DCI Huntley with the same forensic attention to detail that’s become a hallmark of the show.

“I think it’s important to be as close to the right procedures as possible,” says Mercurio. “The starting point is with our advisers and I always get excited if we can use something I haven’t seen in any other series.”


With an eclectic background in medicine and in the RAF before his current television career, Mercurio reckons that we are in a golden age of crime dramas. He is too diplomatic to single out current shows – “there are so many very good ones” – but credits the American series Hill Street Blues, which he watched in the 1980s, as an inspiration in the way it broke away from previous conventions. He also singles out an earlier BBC television drama about anti-corruption cops, Between the Lines, which starred Neil Pearson and won a Bafta in 1994.

The history of the delicate business of investigating corrupt police officers is a long one. When Sir Robert Mark arrived at Scotland Yard as its new commissioner in 1972, he famously announced that it was his intention to “arrest more criminals than he employed”.

This was an era when a “little firm within a firm”, as the bent cops cheerfully described themselves, operated in Britain’s largest police force and corruption, in the shape of accepting back-handers and planting evidence, was rife. In 1973, three members of the Met’s drugs squad were jailed at the Old Bailey and told by the judge, Melford Stevenson, that they had “poisoned the wells of criminal justice… and not the least grave aspect of what you have done is provide material for the crooks, cranks and do-gooders who unite to attack the police whenever the opportunity occurs.”

Worse was to follow. In 1976, a further scandal concerning the “Porn Squad” in Soho led to the departure of more than 60 Scotland Yard detectives. Gilbert Kelland, the then assistant commissioner of the Met, said later, “We strongly believed that, for the eventual benefit of the force, the crow of corruption had to be nailed to the barn door to convince and remind everyone of the need for positive action and eternal vigilance.”

Twenty years later, another commissioner, Sir Paul Condon, told a House of Commons select committee in 1997 that there could still be more than 200 wrong ’uns on the payroll. “I honestly believe I command the most honourable large city police service in the world,” he said. “However, I do have a minority of officers who are corrupt, dishonest, unethical… They commit crimes, they neutralise evidence in important cases and they betray police operations and techniques to criminals… they are very difficult to target and prosecute.”

So how are those “rotten apples” spotted and plucked? The names of anti-corruption branches have changed over the years. In the Met, what was once called A10 was replaced by CIB1 and CIB2 and is now the less snappy Directorate of Professional Standards.

Other forces also have their own Professional Standards Departments, although smaller, provincial forces may pool their resources. The nicknames for these units have changed, too. Once they were the “Ghost Squad” or the “Untouchables” and their detectives known as the “rubber heels” because of the unobtrusive way in which they had to operate. In their less effective days, some were dismissed by cynical detectives as “the muppets”.

What do their fellow officers think of them?

“CID officers used to be reluctant to apply for this department because it wasn’t seen to be the right thing to do and was regarded as a betrayal,” says one former Flying Squad detective, who is a fan of Line of Duty. “Uniformed officers did apply, which resulted in an imbalance of investigators, built on a false premise that uniform were out to get the CID – and no decent detective would want to be part of that. But in the 1990s, the culture started to change and therefore the job was no longer seen as a betrayal of their colleagues. It’s now accepted by all that corrupt officers have to be weeded out, so it’s seen as a good career move.”


A major challenge for any anti-corruption squad is persuading victims of police skulduggery to trust them. When I was The Guardian’s crime correspondent in the 1990s I investigated allegations that some officers at Stoke Newington police station in north London were planting evidence on people and dealing in drugs themselves. After interviewing some of those making the claims, I was told by a lawyer that a senior officer from what was then called CIB (Complaints Investigation Bureau) wanted to meet.

It turned out that CIB had already mounted a major inquiry into Stoke Newington, code-named Operation Jackpot, and they knew I was talking to people, some of whom were in prison, and many of whom were very wary of talking to coppers – any coppers. Could I pass on the word to them that this was a serious inquiry and their confidences would not be betrayed? They also wanted to trace a witness known then only by his street name. I believed that it was a genuine attempt to nail the guilty (like those Line of Duty investigations) but those making the allegations remained understandably cautious.

A small number of officers were eventually prosecuted and jailed and 13 people had their convictions quashed at the court of appeal and paid more than £500,000 in damages by the Met police. It was a reminder that, when the police investigate the police, not everyone is convinced they will do so without fear or favour.


Former Detective Superintendent Graham Satchwell, who was himself investigated and cleared by several internal inquiries, says that “the more ‘results-driven’ detective officers saw internal investigation people as – at best – a nuisance”.

Satchwell, author of the recent memoir An Inspector Recalls, adds that “the abiding memory of those who investigated me is of incompetence and stupidity. Those who run internal complaints departments are always close to the most senior ranks, so whatever they do is authorised. Invariably now, such work attracts ambitious officers.”

Certainly allegations of malpractice are taken much more seriously now than was once the case. Back in 1955, when Superintendent Bert Hannan produced a report on corruption in London’s West End, the then Met commissioner, Sir John Nott-Bower, went to the station concerned and stood on a chair to reassure the troops that he did not believe a word of it. It would be a foolhardy commissioner or chief constable who did the same today.

So in the new Line of Duty, Hastings, Arnott and Fleming will have the daunting task of reassuring us that they are more than capable not only of catching bent cops but of nailing that crow of corruption firmly to the barn door.


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