A pproximately 30 minutes into the first episode of the BBC’s returning Caribbean whodunit Death in Paradise, a warm cosy feeling comes surging in. As is traditional on Robert Thorogood’s sun-kissed thriller, a brutal and confounding murder has been committed. Several suspects are under scrutiny, each with their own knotty motives. Things are verging on complicated.

But we’re reaching the end of a long week in January. Our attention spans aren’t what they used to be. Death in Paradise is perfectly aware of that. So here’s Detective Inspector Jack Mooney (Ardal O’Hanlon) clomping to the rescue of the fading viewer.

He writes the names of all the potential guilty parties on a whiteboard, along with their possible reasons for doing the deed. He even draws arrows, so that we know precisely how the possible perpetrators are interconnected. You settle a little deeper into your chair, knowing you are in safe hands.

There is, it is fair to say, a range of opinions regarding Death in Paradise, which begins its ninth series tonight. It regularly draws audiences in excess of 8 million, placing it comfortably in the top 10 most-watched shows on terrestrial TV during its time on air.

The 30 best TV shows of the decade Show all 30 1 /30 The 30 best TV shows of the decade The 30 best TV shows of the decade 30. Homeland (season 1, 2011) Few dead horses have been more flogged, but if you stretch your mind back enough, it is possible to remember a series with a fantastic premise that kept us guessing for 12 whole episodes. The question: had returning war hero Sgt Brody (Damian Lewis) been radicalised in a foreign jail cell? CIA officer Carrie Mathison (Claire Danes) thought so, but she had plenty of problems of her own. I still think it would have been better if he'd detonated at the denouement. Twisty, compelling, briefly essential. (EC) Showtime The 30 best TV shows of the decade 29. Mum (2016-2019) The slow-burning relationship between Cathy (Lesley Manville), a widow and mother of superhuman forbearance, and her late husband’s best pal Michael (Peter Mullan) elevated what could have been a run-of-the-mill suburban comedy into a beautifully composed portrait of friendship, grief and mid-life romance. (FS) BBC The 30 best TV shows of the decade 28. Handmaid's Tale (2017- ) Hulu’s adaptation of Margaret Atwood’s 1985 novel, set in a pious patriarchal state, lost its way in the second series, but the first, which arrived a few months after Trump entered the White House, was a triumph. As Offred, Elisabeth Moss seethed under her mask of impassivity, while the rich palette gave us a dystopian nightmare as imagined by the 17th-century Dutch school. (FS) Hulu The 30 best TV shows of the decade 27. Money Heist (2017- ) Perhaps the trashiest show on this list, but trash of the highest grade, Money Heist is Netflix's most popular non-English series, a hit across Europe and South America, with 34m accounts watching this year's Part 3 in its first week of release. A mysterious mastermind known as The Professor gathers together a crew of misfit criminals to execute a robbery on the Royal Mint in Spain. Tense, funny, clever and often completely preposterous, La Casa del Papel has only been held back by its off-putting English title. (EC) Netflix The 30 best TV shows of the decade 26. Rick and Morty (2013- ) It unfortunately inspired some of the worst fans on the internet, but that shouldn't detract from Rick and Morty's inventiveness. Ostensibly a parody of Back to the Future, about the adventures of a young boy and his alcoholic, mad scientist grandfather, the cartoon uses its set-up to put its heroes in an endless number of frenetic, frequently insane situations. Blink and you miss a gag and two pop-culture references. (EC) Adult Swim The 30 best TV shows of the decade 25. The Returned (2012-2015) This exquisite French series is about the dead trying to return to their old lives in a secluded mountain town dispensed with the usual gory zombie tropes, instead dwelling on the human instincts of these confused beings – specifically their desire to love and be loved ­– and the grief experienced by those they left behind. (FS) Channel 4 The 30 best TV shows of the decade 24. Catastrophe (2015-19) Sharon Horgan and Rob Delaney were a masterful double act in this sitcom about a holiday fling resulting in an unplanned pregnancy. The pair’s attempts to build a life together yielded scabrous gags about sex and post-partum leakage, a cameo from the late Carrie Fisher and an underlying tenderness that resisted spilling into sentimentality. (FS) Channel 4 The 30 best TV shows of the decade 23. Killing Eve (2018-) A wicked cocktail of comedy and humanity, shock and gore, the first series of Killing Eve, written by Phoebe Waller-Bridge, was a subversive joy. Sandra Oh and Jodie Comer played, respectively, a spy and an assassin whose continental game of cat-and-mouse was a blood-spattered love story for the ages. Sadly, when Waller-Bridge handed off writing duties in the second series, the magic wasn't quite the same. (FS) BBC/BBC America The 30 best TV shows of the decade 22. Borgen (2010-2013) The Killing may have started the Scandi craze, but it aired in Denmark in 2007, so it doesn't count for these purposes. Borgen was everything The West Wing wasn't: a cliché-resistant drama that showed politics in grating reality, with plenty of plausible schemers in slick outfits and a wonderful central performance by Sidse Babett Knudsen as Birgitte Nyborg, the Prime Minister trying to balance principles with power. (EC) DR Fiktion The 30 best TV shows of the decade 21. Detectorists (2014-17) Following the exploits of Lance (Toby Jones) and Andy (Mackenzie Crook), dedicated treasure hunters and members of the Danebury Metal Detecting Club, Detectorists was about people and their passions, community and camaraderie. It’s a wonderfully tranquil meditation on male companionship. (FS) BBC The 30 best TV shows of the decade 20. The Americans (2013-2018) Where other series burn brightly and fade after a couple of years, FX's Cold War spy drama took its time. Matthew Rhys and Kerri Russell, married in real life, shone as the Russian couple working as spies in suburban Washington DC. The tension built over six seasons to a magnificent finale, rewarding those who stuck with it. (EC) Patrick Harbron/FX via AP The 30 best TV shows of the decade 19. The Leftovers (2014-2017) The premise is one of the most intriguing in television: people struggling to come to terms with something called the "Sudden Departure", a mysterious event in whichtwo per cent of the world's population simply disappeared. Damon Lindelof and Tom Perrotta's drama received iffy reviews at first, but its reputation grew through its second and final outings, with writing and performances that explored the full depth of the setup without losing the pervasive air of mystery. (EC) HBO The 30 best TV shows of the decade 18. The Crown (2016- ) The third series is a noticeable drop-off in quality, but for two series The Crown achieved a number of unexpected feats. It made viewers genuinely interested in the Royal Family, and not in a Prince Andrew "should they go to prison?" kind of way. With sumptuous sets and costumes and some excellent performances, especially Claire Foy as the young monarch, this remains the high-water mark of Netflix polish – proof that money can, sometimes, buy you love. (EC) Netflix/PA The 30 best TV shows of the decade 17. The Great British Bake Off (2010- ) Reports of the death of TV’s baking behemoth have been greatly exaggerated: despite host departures, a channel move and the off-screen antics of a certain perma-tanned judge, this big-hearted competition in which friendships are forged and adults weep over sagging soufflés remains the ultimate feel-good reality show. (FS) Channel 4 The 30 best TV shows of the decade 16. The Trip (2010- ) Two men bicker over bottles of fine wine. Steve Coogan and Rob Brydon’s low-key, semi-improvised and implausibly funny tours of high-end European restaurants saw the pair’s insecurities deliciously laid bare as they discussed sex, ageing and ambition. Michael Winterbottom directed. (FS) IFC Films The 30 best TV shows of the decade 15. Happy Valley (2014- ) This Yorkshire-set, Bafta-festooned series gave us Catherine Cawood (Sarah Lancashire), a pleasingly complex, no-nonsense police sergeant up to her neck in rapists, murderers, addicts and the odd ailing sheep, together with some superbly earthy dialogue courtesy of writer Sally Wainwright. (FS) BBC The 30 best TV shows of the decade 14. Girls (2012-2017) Without Girls there is no Fleabag or Adam Driver, and it would probably merit inclusion on those two facts alone. But Lena Dunham now attracts as much opprobrium as praise, and it's easy to forget how new her breakthrough comedy felt in its naturalistic depiction of young women in New York. This was Sex and the City for people who spent more time on Instagram than at work, created by people the same age as those they were portraying. Its look and feel have cast a long shadow. (EC) Rex Features The 30 best TV shows of the decade 13. Sherlock (2010- ) Witty, inventive and dazzling to look at, Steven Moffatt and Mark Gatiss’s relocation of the Arthur Conan Doyle stories to the present day worked beautifully, as did the casting of Benedict Cumberbatch as the “high-functioning sociopath” Holmes and Martin Freeman as the put-upon army veteran Watson. While later series would drift, the first three were unbeatable. (FS) BBC The 30 best TV shows of the decade 12. Chernobyl (2019) A five-part drama about a nuclear disaster in 1986 is not the most promising prospect for a night in with a bottle of wine. It is a tribute to the writer, Craig Mazin, and director, Johan Renck, as well as its cast, especially Jared Harris, that Chernobyl managed to be totally gripping, with frequent moments of stark, horrendous beauty. (EC) HBO The 30 best TV shows of the decade 11. Atlanta (2016- ) At first, the musician and comedian Donald Glover's series about struggling rappers in Atlanta looked like a familiar, safe kind of sitcom about loveable losers. But it quickly evolved into something fresh: a smart, occasionally surreal examination of life at the margins of America, whose angry heart never spilled into preachiness or got in the way of the jokes. (EC) AP The 30 best TV shows of the decade 10. Love Island (2015- ) Who could have anticipated a dating show in which twenty-somethings sit around in microscopic swimwear would tell us so much about the human condition? Gaslighting, bromances, the complexities of “girl code” – Love Island delved beneath the spray tans and schooled the nation on modern manners. (FS) Rex Features The 30 best TV shows of the decade 9. Patrick Melrose (2018) An electrifying study of addiction, trauma and the corrupting power of privilege, based on the autobiographical books by Edward St Aubyn. Benedict Cumberbatch played the feckless antihero grappling with his past and trying (and mostly failing) to be better than the wretched aristos that raised him. (FS) Sky The 30 best TV shows of the decade 8. The Vietnam War (2017) Ken Burns's epic 10-part documentary followed up his other conflict opuses, on The Civil War and The War, with a detailed story about Vietnam. Using new interviews from both sides as well as archive footage, the documentary shows in unrelenting detail a catastrophe that unfolded in slow motion. Some critics accused it of underserving the experience of the Vietnamese civilians. But it left viewers in no doubt that not only did the US leadership pursue it long after it was a lost cause, but they knew from the start it was unwinnable. (EC) Trailer screenshot The 30 best TV shows of the decade 7. Black Mirror (2011- ) Charlie Brooker sent every other TV critic, or at least one of them, into a spiral of envy by proving not only that it was possible to cross over into creation, but to do so in style. Black Mirror's taut near-future tales of techno-dystopia are almost always interesting, even if they sometimes fall short of their ambitions, as with the high-concept recent film, "Bandersnatch". The best episodes, like 2016's tour de force, "San Junipero", are gripping examinations of human connection in a world where interactions are increasingly by screens. (EC) Getty Images The 30 best TV shows of the decade 6. Blue Planet II (2017) The first of the Attenborough documentaries to speak directly of the human impact on the natural world, this kaleidoscopic ocean odyssey provided a visual feast of clam-cracking tuskfish, alien-looking pyrosomes and anthropomorphic ­dolphins, while reminding us how it could all be lost. (FS) BBC The 30 best TV shows of the decade 5. BoJack Horseman (2014- ) Only in a world of Netflix budgets can you imagine a concept as wild as BoJack Horseman’s getting off the ground. It's a cartoon set in LA, ostensibly a comedy about celebrity, except half the characters, including its lead, are anthropomorphised animals. Halfway through its final season, which has been split into two, its initial zaniness has given way to something darker and more interesting. Lurid colours and visual wit dress one of the most humane explorations of depression, addiction and cycles of abuse. (EC) Netflix The 30 best TV shows of the decade 4. Fleabag (2016-19) What began, in its first series, as an enjoyably acid-tongued portrait of modern womanhood became a fully fledged masterpiece in the second. Written by and starring Phoebe Waller-Bridge, Fleabag gave us perfectly calibrated scenes of familial dysfunction and sexual longing – the latter memorably culminating in the Priest’s simple, thrilling instruction: “Kneel.” (FS) BBC The 30 best TV shows of the decade 3. This is England (2010-15) The first spin-off series from Shane Meadows’ 2007 film, about a gang of ex-skinheads from the Midlands, was set during the 1986 World Cup, and remains one of the great British dramas, depicting working class lives with humanity and humour. This is England ’88 and ’90 followed, both of them similarly infused with heart and soul. (FS) Channel 4 The 30 best TV shows of the decade 2. Succession (2018- ) Said to have been a decade in the making, Succession is worth every minute spent on it. Brian Cox enjoys a dream of a late-career role as Logan Roy, the ageing media tycoon unwilling to relinquish control of his company to any of his ungrateful and talentless children. There's oblivious eldest son Connor (Alan Ruck), troubled addict Kendall (Jeremy Strong), scheming daughter Shiv (Sarah Snook) and abrasive youngest Roman (Kieran Culkin), along with a host of hangers-on, partners and support staff. None of them seem to have the right stuff. It's an intriguing set-up, but Succession is lifted by its script, performances, locations, costumes, music and direction, which place it firmly in a tradition of laughing at our rulers, where the mirth comes tempered with the knowledge that these are really the people in charge. (EC) Graeme Hunter The 30 best TV shows of the decade 1. Game of Thrones (2011-2019) Yes, the final series went a bit weird. Maybe the final two series. A case could be made that the TV adaptation was never as emotionally resonant when it went beyond George RR Martin's novels. The final series were only disappointing compared to what had come before, which was a fantasy on an unprecedented scale that managed to be grandiose without slipping into melodrama. An invented universe with necromancers, dragons, magic swords and ice zombies was notable for its plausible realpolitik. At a time when viewing tastes were meant to be becoming more atomised, Game of Thrones was global event TV, which made household names of the Starks, Lannisters and Greyjoys and provided a whole generation of English character actors with a regular income. (EC) AP

Yet critics are generally flabbergasted by its popularity – when they deign to acknowledge its existence. Among those who make it their business to know the difference between good and bad television, there is widespread bafflement that an easy-to-follow thriller set on a gorgeous Caribbean island should find favour with the public.

The puzzle of Death in Paradise’s appeal is, in fact, easily cracked. For all its impressive body-count, Thorogood’s romp harks back to breezier and more innocent times. Each week a fresh crime is committed on Saint Marie, a fictional setting loosely based on the French-governed archipelago of Guadeloupe (where Death in Paradise is filmed).

Enter Detective Inspector Mooney, that rare modern TV detective whose personal life is not a distracting mess. As with his two predecessors on the show – played in chronological order by Ben Miller and Kris Marshall – he disentangles the mystery, the killer is unmasked. All before the news and bedtime.

To say I’m an obsessive Death in Paradise fan would be an exaggeration. I did not spend December counting down to the latest series. Nor did the revelation that Ardal O’Hanlon is moving on after three years – apparently the relentlessly sunny weather is too much – send me to the internet to vent my outrage. The news that he is to be replaced by Royal Family star Ralf Little wasn’t a topic of conversation with my friends in the pub over Christmas. There is no Death in Paradise expanded universe to become immersed in. Once done, each episode immediately erases itself from your memory.

Ardal O’Hanlon as DI Jack Mooney in the show (BBC/Red Planet/Denis Guyenon)

But if it’s on and I’m not doing anything else – such as meaningfully engaging my brain – then, sure, I’ll watch. Such, I suspect, is the general feeling among its regular viewers. They, like me, may enjoy being reminded of such uncomplicated treats of yesteryear as Bergerac, Lovejoy or Murder, She Wrote​. The world is angry and frightening, full of people shouting at one another on Twitter. Death in Paradise presents an irresistible weekly escape hatch.

It has a charming backstory too. In the mid-Noughties, Thorogood was nearing 40 – a struggling writer beginning to suspect he was wasting his life. His wife, a broadcast journalist with Classic FM, was supporting the family. His days were spent knocking around in his pyjamas writing scripts he knew would never amount to anything.

Then, one morning in 2007, he happened to switch the radio on and hear a news report about the suspicious death of Pakistan cricket coach Bob Woolmer at the Cricket World Cup in Jamaica. The detail that intrigued him was that local police had brought in detectives from Scotland Yard to help with the murder investigation (it was never proved conclusively whether or not Woolmer was the victim of a crime). In his bedroom office, where he was wrapped in his dressing gown and feeling slightly sorry for himself, a light-bulb went off.

“I imagined an uptight and by-the-book London copper trying to solve a murder in the sweltering heat of the Tropics. There was a series in this. I was sure of it,” Thorogood later told the BBC.

So he had the germ of something. But how to sell it? He started knocking on production company doors. They saw the potential – but also balked at the costs such an undertaking would necessitate.

Josephine Jobert and Kris Marshall appeared together in three series of the programme (BBC/Red Planet Pictures/Denis Guyenon)

“They liked the idea enough, but it would be expensive to make, it would require filming in the Caribbean for at least five months,” he later remembered. “And there was one thing they believed above all else: it was unlikely the BBC would allow someone without a writing credit to their name to create and write a prime-time TV series.”

Salvation came in the unlikely form of a script-writing competition organised by Tony Jordan, former lead writer of EastEnders, through his new production company Red Planet Pictures. Jordan, who was also the co-creator of Life On Mars, pledged to give his full backing to any screenplays that caught his attention. Which Thorogood’s outline for Death in Paradise did.

Death in Paradise: series 9 - trailer

With Jordan vouching for the project, the BBC and France’s national broadcaster France Televisions agreed to co-fund the production, Thorogood had his green light. A few months later, he was in the Caribbean scouting locations. The series debuted on 25 October 2011, drawing an impressive 5.89 million viewers. That figure had jumped to more than 7 million when it returned in January 2013 (from the outset it was decided to maximise the appeal of the sun-slathered backdrop by airing in the bleak midwinter).

For all its success, Death in Paradise has found it comically difficult to hold onto its stars. First to play the archetypal copper out of water was Ben Miller. But he left in 2014 to be with his partner back in London. He had spent 12 of the previous 18 months shooting in Guadeloupe. Enough was enough. So his character, DI Richard Poole, was killed off and Kris Marshall’s detective Humphrey Goodman flown out to investigate. But Marshall, likewise, found the strain of being away from loved ones too much and, with his family starting to grow up, packed in the show in 2017.

Next came Father Ted star and successful stand-up ﻿Ardal﻿ O’Hanlon. He transplanted the agreeable befuddlement of Ted’s Father Dougal McGuire to the Caribbean. The result was a sort of Celtic Columbo (for those sufficiently ancient to remember Peter Falk’s wily homicide detective).

But the boundless sunshine and beauty of Guadeloupe apparently weren’t to the actor’s liking. He has stated it was “time to move on and explore other opportunities – preferably nearer the Arctic Circle”. He is to be replaced by former Royal Family star Ralf Little at some point in the present season. It’s like the James Bond conveyor-belt sped up by a factor of 10.

Nor is it just the leads that keep flying the tropical coop. Sara Martins, who played DI Poole’s original investigating partner DS Camille Bordey, left a year after Miller. She said she wanted to try different things. “The only way to grow in life is to take risks, even if it means losing something you love, or leaving a place that’s comfortable. You should always go forward and take new challenges.” A similar restlessness appears to have taken hold of Danny John-Jules, who walked away from the part of officer Dwayne Myers after seven years. Shortly afterwards, he turned up on Strictly Come Dancing.

Yet far from a curse, Death in Paradise’s inability to hold on to major cast members has proved an unlikely blessing. The BBC received definitive proof early on that the series is bigger than any one actor. In theory, this is a hit that could rumble on in perpetuity (at least one further series has already been confirmed). For as long as there is an appetite for elaborate murders committed amid golden sands and aching sunshine, the broadcaster can continue churning out Death in Paradise. Thorogood’s mid-life crisis pipe-dream has birthed that rarest of things: the unkillable franchise.

“There’s something wonderful about that sort of Poirot, Agatha Christie-style investigation: cross-questioning all the witnesses and checking their stories, looking for means, motive and opportunity,” was how original star Miller defined the allure of Death in Paradise when initially cast. “It’s got that wonderful classic feel to it, at the same time as this incredibly unusual tropical island setting and a very remote tropical island at that, remote in the geographical sense. It feels like a different time and place.”