J ason Watkins is walking on his hands. We’re in a stuffy conference room to discuss the 53-year-old’s new murder mystery series, McDonald & Dodds – but instead, dressed in a crisp white shirt, he’s tipped himself upside down.

“The trick is to sort of rock forward and then almost fall over and run,” he pants. “I timed it once and got within a second or two of the world record for running across a basketball court.”

It’s not too late to try again.

“No, it is,” he says, rubbing his wrists and returning to his seat. “It used to be a party trick. It’s confusing for people because I’ve got glasses and I play geeky intellectuals and professors and weirdos.”

That does seem to have become his USP. The actor earned a Bafta for his role as the eccentric, misunderstood landlord who was falsely accused of murdering his tenant in The Lost Honour of Christopher Jefferies. And in The Crown, which was also written by Peter Morgan, he played enigmatic prime minister Harold Wilson to uncanny effect.

The 20 greatest TV cop shows of all time Show all 20 1 /20 The 20 greatest TV cop shows of all time The 20 greatest TV cop shows of all time 20. Ironside (1967-75) Launched to much fanfare as a television movie and boasting a killer theme tune from Quincy Jones, Ironside starred Raymond Burr, who was still hot after his stint as television’s Perry Mason, as San Francisco Chief of Police Robert T Ironside, who is confined to a wheelchair after an attempted assassination. Over 199 episodes, the series followed Ironside and his team in his role as consultant to the Police Department as they sorted out the bad guys of the City by the Bay. NBC The 20 greatest TV cop shows of all time 19. Rebus (2000-09) Ian Rankin says he has never watched any of the television adaptions of his famously brooding, heavy drinking, loner detective because he didn’t want the actors’ faces replacing how he envisaged Rebus in his head. Two actors have played Rebus on screen, John Hannah and Ken Stott. Hannah gives the role his best but was probably too young and lacked the cynical gravitas that Stott gave to Rebus. With similar roles in The Vice and Messiah giving Stott an identifiable acting persona, he perhaps has the same problem as Humphrey Bogart being too much like Bogart to play the definitive Philip Marlowe, but in the absence of any other candidates, Stott is just fine. Rankin’s central theme of the Jekyll and Hyde dichotomy of Scotland’s capital city remains intact, and as in the novels, the real star of the show is of course, Edinburgh itself in all its historic beauty, showing the dark underbelly of the city behind the chintz curtains. The 20 greatest TV cop shows of all time 18. Life on Mars (2006-07) Nostalgia might not be what it used to be, but the biggest mystery with Life on Mars is why it took someone so long to come up with this inspired paean to the pop culture and TV cop shows of the 1970s. Throw in the fish-out-of-water time travel motif and the tongue in cheek non-PC scripts and characters, and its not hard to see why the series struck a chord with audiences. BBC The 20 greatest TV cop shows of all time 17. Luther (2010-16) Like many of his ilk, dedicated near-genius DCI John Luther (a brilliant Idris Elba) is a tormented soul, struggling with his own inner demons, hugely affected by the stomach churning crimes he investigates. Luther is so obsessive that he will do anything to get his man (or woman, in the case of his nemesis, the psychopathic scientist Alice Morgan (Ruth Wilson) Both cerebral and heart pumping, Luther was created by Neil Cross and has spawned American and Russian versions. BBC The 20 greatest TV cop shows of all time 16. The Fall (2012-16) Gillian Anderson is the deliberate, dedicated senior detective on the trail of an equally meticulous serial killer in this controversial drama filmed and set in Northern Ireland. The Fall survived accusations of misogyny and voyeurism to lift a Bafta for best television drama and keep viewers hooked for three series, but remains a troubling, unsettling experience for many. The 20 greatest TV cop shows of all time 15. Cagney and Lacey (1981-88) The cop show that more than any other blew the stereotypical image of female police officers out of the water, and challenged the sexist attitudes of many executives in the television industry. Tyne Daly and Sharon Gless won the hearts of millions of viewers, and six Emmys between them, as two dedicated New York police officers who happened to be women with normal lives and challenges like everyone else. The bond between the two characters was unbreakable despite leading entirely different lives (Lacey was married with a family and supportive husband, Cagney drifted from relationship to relationship). A game changer in many ways, Cagney and Lacey explored issues such as rape, abortion and Cagney’s alcoholism head on. The 20 greatest TV cop shows of all time 14. Between the Lines (1992-94) Set in the Metropolitan Police Complaints Investigation Bureau, the Bafta winning Between the Lines follows ambitious Chief Superintendent Tony Clarke and his team as they investigate corruption within the police force. Between the Lines drew praise for the way it tackled topical issues of the day as it attempted to address the age old moral dilemma, quis custodiet ipsos custodes – who will guard the guards themselves? The 20 greatest TV cop shows of all time 13. The Shield (2002-08) The cop show that more than any other blurred the lines between the good guys and the bad guys. Rogue cop Vic Mackey leads the elite “strike force” of LA detectives who routinely break the law to keep the streets safe, but also to feather their own nest. There are subplots aplenty, and Mackey’s downfall plays out almost like a Shakespearean tragedy. The 20 greatest TV cop shows of all time 12. Z Cars (1962-78) Set in the fictional northern town of Newtown, Z Cars broke new ground in police drama shows, challenging the homely predictability of the likes of Dixon of Dock Green. Devised by Allan Prior and Troy Kennedy Martin, the series centred on not just one central protagonist, but rather several police officers both uniformed and plain clothed. Z Cars brought some iconic characters into the nation’s living rooms such as detective Charlie Barlow, PC “Fancy” Smith and desk sergeant Bert Lynch. The police officers themselves were portrayed warts and all, with gritty subject matter, including domestic abuse at the hands of a police officer, at the heart of the storylines. The actors became household names with the iconic theme tune whistled on everyone’s lips, and of course there were the “Z” cars themselves, the American-style Ford Zephyr and Zodiac patrol cars. The 20 greatest TV cop shows of all time 11. Prime Suspect If Cagney and Lacey blazed the trail for female cops, then the first series of Prime Suspect in particular indicated a seismic shift in the perception of, and the attitudes towards, the female police officer. Helen Mirren is outstanding as DCI Jane Tennison who heads a murder squad hunting a sadistic serial killer, but has to overcome opposition and resentment from her team as well as the institutionalised sexism of the police department itself. Subsequent series concentrated more on Tennison’s inner demons as she began to rely on alcohol to help her cope with the pressures of the job. The 20 greatest TV cop shows of all time 10. The Killing (2007-12) This Danish police procedural and prime example of Scandinavian noir attracted criticism for its violence against women. It did, however, become an international success particularly in the UK. Viewers were gripped by the formula; that of each episode reflecting 24 hours in the same murder case, and by the cold-fish female detective protagonist Sarah Lund, while developing an almost fetishist fascination with her knitwear. The Killing paved the way for other subtitled European crime dramas and equally popular and acclaimed entries such as The Bridge and Borgen quickly followed. The 20 greatest TV cop shows of all time 9. Law and Order (1990-2010) Filmed in New City with a two-pronged approach of the investigation of a crime and arrest of a suspect, followed by the suspect’s trial, Law and Order introduced one of the great small-screen detectives, recovering alcoholic Lennie Briscoe. (Jerry Orbach). The show’s boast was that many of its subject matters were “ripped from the headlines” and it was this approach that gave it a compelling topical feel and made it the longest-running American crime series and the benchmark for police procedurals. The 20 greatest TV cop shows of all time 8. Line of Duty (2012- ) An outstanding ratings success for BBC2, Jed Mercurio’s masterful police corruption thriller gripped viewers from the very beginning and kept them guessing until the explosive climax to the third series. The bold, serpentine and gripping storylines provided the exemplary cast with parts of a lifetime, with the most outstanding feature of Line of Duty undoubtedly the lengthy interrogation scenes as the tension was racked up notch by notch. PA The 20 greatest TV cop shows of all time 7. Columbo (1971-2003) After Bing Crosby turned the role down, Peter Falk became synonymous with the cigar smoking, dishevelled police lieutenant in a shabby raincoat, winning four Emmys and a Golden Globe. Referred to as a “howcatchem” by its’ creators, Columbo deviated from the traditional whodunit in that the audience and, it seemed, Columbo himself, knew the identity of the murderer from the start. Half the fun of the show was watching the murderer (frequently an A- or B-list guest star) underestimate the seemingly bumbling, absent-minded detective while he baited the trap to snare them. Oh, and just one more thing, as Columbo himself might say: although Columbo routinely spoke of his wife, she was never seen in any episode, but the character was later given her own, short-lived, spin-off show, Mrs Columbo. The 20 greatest TV cop shows of all time 6. The Wire (2002-08) It has been compared to the works of Dickens and Dostoevsky and lauded as the greatest television programme ever. But the triumph of The Wire is how it tells the story of the decaying city of Baltimore through the lives of the police, drug dealers, politicians, children and the dispossessed, making no moral judgements between good and bad in a predominately grey world. The Wire may not be the greatest television programme ever, but its realism and authenticity can never be in doubt. In 2005, members of a drugs gang claimed they had studied The Wire in order to learn about the latest police surveillance techniques, surely the ultimate example of life imitating art. The 20 greatest TV cop shows of all time 5. NYPD Blue (1993-2005) Aping its antecedent Hill Street Blues’ cinema verite style, multi award winning NYPD Blue was a natural progression for co-creator Steven Bochno, who along with David Milsch came up with even grittier storylines, atmospheric New York locations and warts ’n all characters to create a hugely compelling and influential cop show. But let’s be honest, despite a terrific ensemble cast, Dennis Franz as scenery-chewing recovering alcoholic detective Andy Sipowicz, was virtually the whole show, appearing in all 261 episodes and in the process searing his psyche in viewers’ minds. Getty The 20 greatest TV cop shows of all time 4. Homicide: Life on the Street (1993-98) Baltimore native Barry Levinson was a natural fit as executive producer of this ultra-realistic police procedural, based on The Wire creator David Simon’s book chronicling his experiences following homicide detectives at work in the so-called “City of Firsts”. From the very first episode Life on the Street succeeded in dispelling the myths and stereotypes about the television cop, showing that murder and violence were just a routine parts of the job. Indeed the murder of a schoolgirl in that first episode was never solved. Aficionados rate this show even better than The Wire. Some have called Homicide: Life on the Street the missing link between Hill Street Blues and The Wire. Beg, borrow or steal the box set and find out why. The 20 greatest TV cop shows of all time 3. Inspector Morse (1987-2000) Such is the renown of the celebrated television adaptation of Colin Dexter’s novels featuring the enigmatic real-ale swilling, arts loving, crossword buff detective, that there’s very little left to say apart from it’s basically a brilliant variation on the classic English whodunit, Kevin Whately’s Lewis is to John Thaw’s Morse as Dr Watson was to Sherlock Holmes, and Thaw is simply wonderful. Rex The 20 greatest TV cop shows of all time 2. The Sweeney It has become so caricatured and parodied in recent years that it’s easy to overlook the fact that The Sweeney made Z Cars look as antiquated as the former did Dixon of Dock Green a decade earlier. Created by Ian Kennedy Martin, brother of Z Cars co-creator Troy, The Sweeney was shot in 16mm film and that, along with extensive location shooting, gave it a more cinematic look than other studio-bound rivals. Rex Features The 20 greatest TV cop shows of all time 1. Hill Street Blues (1981-87) Created by Steven Bochco and Michael Kozoll and still celebrated, still hugely influential, and still the cop show to which almost everything that has come since owes a huge debt. From Mike Post’s iconic theme and the innovative cinema vèritè-evoking handheld camera, to the brilliant ensemble cast creating beloved characters and dramatic storylines in the urban sprawl of an unnamed US city, Hill Street Blues pioneered a new wave of cop shows. Ironically, it never gained huge audience ratings, but garnered a grand total of 98 Emmy nominations. Groundbreaking, thought provoking, emotional and funny, Hill Street Blues stands tall in the canon of truly great television. Hulton archives/getty images

Watkins joined the show at the same time as Olivia Colman and Tobias Menzies, who dethroned the original lead actors, Claire Foy and Matt Smith. “It was daunting in that it’s the biggest show on the planet,” he says – though he was glad to be spared the pressure of stepping into another actor’s shoes.

“I was liberated from the stuff the regulars have to deal with,” he continues, “although Olivia made her majesty her version of it, and will not necessarily have drawn inspiration from Claire Foy’s characterisation. And the same with Tobias’s take on Prince Philip – it’s different to Matt’s. You take your influence from the real person. My only ghost, in a way, was John Lithgow’s spellbinding performance as Churchill. But it’s different. Churchill was a paternal figure in the Queen’s life and he guided her in those early stages.”

Watkins was at the centre of series three’s most moving episode, which dramatised the Aberfan tragedy and its aftermath. The decision to portray the 1966 catastrophe, in which 116 children and 28 adults were killed after the collapse of a mining waste tip, was not taken lightly. Writer Peter Morgan has spoken of how raw the trauma was for residents – some of whom appeared as extras – during filming. For the first time in 53 years, they were offered counselling.

“We shot the episode in a neighbouring village,” says Watkins. “The extras were all Welsh and from the valleys. All of them I spoke to had a connection. They remember being children and their dads saying, ‘Right, we’re going.’ And they got in the car and drove down to Aberfan and literally started digging…”

Everybody in the cast and crew, he says, wanted to get it right. “It was such a cataclysmic event that I weirdly feel is not remembered enough. We were quite privileged in that we were able to share their story with the world.”

Olivia Colman said that she’d become a “lefty monarchist” after working on The Crown. What about Watkins? “Am I a raging monarchist?” he sighs. “I suppose I’m a pragmatist and would say that this is a society where we have a royal family and we have to… that’s the way it is. I’m as pragmatic as Wilson about it.”

Prince Andrew is off limits, he says. “I can’t talk about him. It’s just impossible. If that” – he points at my Dictaphone – “wasn’t on… I can’t talk about it, that’s all I can say really.”

He can talk about McDonald & Dodds, though. Split into two two-hour films, the series is about a pair of detectives who forge an unlikely and rumbustious partnership. He was drawn to the show, in which he stars alongside Tala Gouveia, because of the “diverse element”. “A young, black female officer with a middle-aged white guy from the middle of nowhere – well, Bath, beautiful Bath – I thought that was an interesting clash.”

On the case: Jason Watkins and Tala Gouveia in ‘McDonald & Dodds’ (ITV)

Many of Watkins’ projects have questioned established institutions – the royal family in The Crown, the church in The Golden Compass, the press in The Lost Honour of Christopher Jefferies. Is it important to him that TV does that?

“You’ve got to earn a living as an actor and I’m not one of those people who just does lots of theatre,” he says. “I love doing television and I’m populist in that way. But that doesn’t mean I don’t have an agenda about what I think is quality and what is important in society. One can contribute to the issues of the day in quite a subtle way sometimes. It doesn’t have to be dogmatic.”

He straightens the cuff of his shirt. It must have gone awry mid-handstand. “You’ve got to do the entertaining first,” he says, “and slip in the other stuff later.”