Death Valley stars Timothy Spall and Gwyneth Keyworth tease "deeper" Chapel and Janie relationship in season 2

This article first appeared in Radio Times magazine.

In a hazy police station atrium in south Wales, police consultant John Chapel and DI Janie Mallowan are confronting a murder suspect. Their evidence? Impeccable. Their psychological profiling? Absolutely top-notch. Surely, they’ll get this “whodunnit” wrapped up in no time.

Except – CUT! – there needs to be another take. As Death Valley stars Timothy Spall and Gwyneth Keyworth wait, a smoke machine revs up again, to create the illusion of a stultifying, overheated summer day inside Trebach Police Station. In reality, it’s a chilly November morning, and Trebach Police Station is a set deep within Roath Lock Studios in Cardiff, fully laid out with corridors, stairs, interview rooms, CCTV nerve centres and offices. There’s even a vending machine filled with real food – apparently, regularly raided by members of the cast.

Not far away lies the cozy cottage of actor-turned-sleuth Chapel, stuffed with mementos from his career including a BAFTA award and two – count them – framed copies of a Radio Times cover from when his fictional TV show Caesar was top of the ratings. Clearly, he’s a man of taste and refinement.

“John’s cottage is just so delightful. It’s so believable as a place,” Spall tells RT – also revealing he has the Caesar cover on the wall at home alongside his two real RT covers. “You would never question that it’s not where it looks like from the outside. It shows how good the production team is in general.”

“I forget that the station is a set,” adds co-star Gwyneth Keyworth, who plays Mallowan, Chapel’s former superfan-turned reluctant police partner. “Sometimes I can go up the stairs, and I’m like, ‘Oh, yeah, it doesn’t actually go anywhere!’ There’s a cut-off point.”

Just as trapped in the episode being filmed today – the fifth of the new series, which starts on BBC One on Sunday – are Chapel and Mallowan themselves, who have to solve a murder that takes place on a police training course. Until they solve it, no one can leave the station.

“That’s kind of our modern homage to those kind of Agatha Christie, And Then There Were None-type stories,” series creator Paul Doolan explains. In general, this cozy whodunnit wears its Christie influences on its sleeve – Keyworth’s Mallowan has the same surname as the Queen of Crime’s second husband – but Death Valley has become a success all of its own.

When the first series debuted last year it had the biggest overnight ratings of any BBC comedy show in five years. Since then, it’s gone worldwide – recently, Spall was collared by three different American fans on a trip to New York.

“I’ve watched it with my grandad, my best friends and my mum,” Rithvik Andugula, who plays DC Evan Chaudhry in the series, tells RT. “Anyone can really watch this show.”

“I was overwhelmed by the overseas response,” says Steffan Rhodri, who plays DCI Barry Clarke and has some experience of Welsh TV breaking through after his stint as Dave Coaches on sitcom smash Gavin & Stacey.

“Gavin & Stacey is so ubiquitous that of course I get stopped for that. But in my everyday life I look more like Clarke than I do like Dave Coaches, because I don’t have the moustache in real life. So people are beginning to know me more for this.”

So, how to follow that success with the Difficult Second Series? Writer Doolan isn’t fazed. He points out that series one had to set up Chapel and Janie’s unusual crime-solving arrangement, and now that the ex-thesp is an official police consultant in series two, there’s less to explain in every episode.

“It’s daunting, but liberating,” Doolan says. “Series two is so much easier because all the parameters are set, and you already know what does and doesn’t work.”

Other mysteries this year include murders in picturesque fishing villages, trendy communes and the local rugby club, as well as – most excitingly – the set of a fictional big-budget Netflix series based on Welsh mythological text The Mabinogion, where Chapel can stretch his acting muscles again.

“There are more laughs, but there are also more stakes in this series,” Keyworth says. “Chapel and Janie both have their flaws, and they spot each other’s flaws, especially in this series, because their relationship is deeper.”

“It’s an unusual relationship,” Spall adds. “There are 30, 40 years between them, but there’s very little generational stuff pulled between them. They’re more like siblings, really, rather than father and daughter or uncle and niece.

“It’s an odd cocktail that really, on the face of it, shouldn’t work – but somehow it does!”

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Death Valley returns on Sunday 17 May at 8:15pm on BBC One and iPlayer.

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