Endeavour writer Russell Lewis on the future of the ITV crime drama: “We know the cards that remain”

"That it doesn’t is testament to the professionalism and expertise of the crack troops who comprise #TeamEndeavour. But we sail close to the wind... at such times, gallows humour comes into its own."

Fans are desperate to know how the series will continue – relations were strained between Oxford detectives DS Morse (Shaun Evans) and his boss, DI Fred Thursday (Roger Allam) at the end of the recent, 1970-set series – but they're in for quite a wait, as Lewis explains.

"The hiatus in production may throw a spanner in the works in terms of the rather happy timeline in which we’ve found ourselves across the past four series – with our story year being exactly 50 years distant from the year of broadcast – but we shall cross that frayed rope bridge over crocodile-infested waters when we reach it. There are some clear waypoints in ’71, if that turns out to be the year we address."

Lewis adds, "Everything is in the planning stage. We know the cards that remain in our hand, and it’s very much a case of arranging the order in which they're played in order to bring about the desired 'grand slam'."

Having written a 1995 episode of the original Inspector Morse series, five screenplays for the spin-off, Lewis, and every single Endeavour to date, he has been steeped in Oxford for 25 years.

Any stand-out moments of fun from filming? "I think we all enjoyed Jeux Sans Frontières [in the 2018 episode Quartet]. A mad morning in a field. A cast of dozens! A properly working Outside Broadcast truck – built and maintained by ex-TV engineers. That was lovely.

"But it’s hard to top a beautiful morning in the Quad at New College, where we filmed the song-and-dance routine Make Believe You Love Me for Mimi’s show [Sharlette Henry, see below]. All these fantastic dancers in their rain capes and galoshes. Top choreography by Sammy Murray with very strong umbrella work. I’m a hoofer at heart."

Since the 2012 pilot, viewers have lapped up not only the serpentine stories and richly detailed period reconstructions – as Endeavour Morse works his way up from detective constable to sergeant – but also the writer's fondness for Easter eggs and metatextual references.

That very first outing proved that Lewis was a great respecter of the show's origins. Abigail Thaw, the daughter of original Morse actor John Thaw, plays Oxford newspaper editor Dorothea Frazil (Frazil is a type of ice, so D. Ice = thaw). Morse's first exchange with her ended as follows – Dorothea: "Have we met?" Morse: "I don't think so." Dorothea: "Another life then..?"

And the most recent series featured a lovely moment in which Dorothea attends the first national conference of the Women's Liberation Movement, and meets its organiser, Sally Alexander. In real life Alexander is Abigail Thaw's mother, but in the episode was played by Thaw's daughter, Molly-Mae Whitmey.

Lewis must have enjoyed writing that scene? "Oh, enormously. Pretty much everything in 1970 built on, or was inspired by, that first Women’s Liberation conference. Lest we forget. Alas, it seems that many have. But it was, and remains, massively, massively important. A singular regret is that I didn’t have Joan Thursday in play, as I expect she would have been front and centre at that gathering."

Lewis adds, "One of the great joys of Endeavour – which on the surface at least, is quite a ‘boysie’ show – is its women. The three who have been part of the story from the start, or as near as damn it – Dorothea Frazil, the mighty Win and Joan Thursday – have given us a bit of a window on womanhood in a small, wet island off continental Europe at a hinge of history.

"It’s something I’d like to have had the time to explore in greater detail if the dead bodies hadn’t got in the way, but certainly Joan’s development has been satisfying to chart and feels truthful to its moment. There's a restlessness there, a hunger for something more than the hand she’d been dealt by dint of her sex and social class. She loves her mother, but she doesn’t want to live Win’s life."

"Win’s heroism is of a different order of magnitude altogether. It's hard to overstate one’s affection for her character. A bit of Housewife 49 about her, I suppose. She’s the kind of woman my grandmother would have stopped to yak with at the Sainsbury’s on the Falcon Road, Battersea – for what seemed to a child like a small eternity.

"The maker of sandwiches, who tended to grazed knees, and fevers, and saw the kids clean and fed and schooled, and kept house, and shopped, and washed and ironed, and never sent Fred out in a three-day shirt… for the most part invisible to the world – but with this extraordinarily rich inner life. When Win speaks her mind, one would be well advised to listen.

"And then we have Dorothea, who is as self-made as it gets. Sometime war correspondent, now fighting the good fight at a provincial newspaper. A woman making her way in a man’s world is such a cliché, but journalism at the time was a pretty blokey affair. It says a lot for Dorothea’s character that she’s achieved all she has in a field crowded with galumphing or resentful chaps. It’s a bit like that line of Ginger Rogers, in that she did all that Astaire did, only backwards, and in heels."

But back to those Easter eggs, or “grace notes and finials”, as he once called them. Does he have any favourites? "There have been so many now – but my favourite was by Sam Costin, my script editor across the first three series. It was so beautifully elegant and witty. The mattress at Burridges department store tested by Endeavour and his then girlfriend Monica (Shvorne Marks) was 'the Silent Spring’. A quick Google should bring readers to the fun of it.

"We nodded to Trumptonshire, because I grew up on it, and because 1969 was the year that Chigley, the last of Gordon Murray's trilogy, was broadcast. A hearkening back to some lost, bucolic, Elysium. In Confection we put it front and centre.

One of the most lavish homages was the 2019 episode Apollo, which was an extended love letter to Gerry and Sylvia Anderson's puppet series of the 1960s. "Absolutely," agrees Lewis. "It was very much my era. So, working with Stephen La Rivière and his extraordinary team at Century 21 Films – together with having the Andersons' original collaborators, director David Elliott and puppeteer Mary Turner, with us on the studio floor – was one of the highlights of a very long time in showbusiness. Given half a chance, I would spend my remaining days making Supermarionation shows."

Are there any references he thinks he managed to slip past the scrutiny of loyal fans? "Some, I’m sure. Maybe it was easier in the early series when the audience hadn’t quite tumbled to our mischief, but in general, people are pretty good at spotting them.

"Sam Costin and I have a shared fondness for Joe Orton, the films of Lindsay Anderson and Kubrick, noir cinema, and 'women’s pictures’ of the 40s and 50s. So little nods crept in. Perhaps fewer in the last run [the series seven trilogy], as the whole opera felt like a massive bit of skulduggery on our part, and we didn’t want to over-Easter-egg the pudding.

"But I’m glad to report that there is a fair bit of that type of mischief waiting in the wings [for series eight]. A little more sunshine across the board. Heaven knows we’ll all be ready for it by then."

As to what else we might expect to see reflected in Morse's onward journey... "the jump to decimalisation and intimations of our joining the European Community... I’m unhealthily obsessed with that early 70s aesthetic... It’s the world of Peter Serafinowicz and Robert Popper's Look Around You... An era of Doomwatch, and Nigel Kneale’s The Stone Tape..."

What about the TV series and screenwriters that made an impression on the young Russell Lewis? It's a huge list, which includes Play for Today, the Dennis Potter dramas (Pennies from Heaven, Blue Remembered Hills, The Singing Detective), Mike Leigh, Alan Clarke, Ken Loach, Steven Poliakoff’s Bloody Kids, Alan Bennett... In short, "Oh my goodness. Everything! Between the 60s and 70s, I was just a living VCR with its button stuck on record."

And crime writers? "I guess everything has an influence – for good or ill. Agatha Christie, as a kid. Those Tom Adams covers had me hooked. Around 1975, the BBC aired the Ellery Queen Whodunit series, which was fantastic, if short-lived. Conan Doyle, naturally. Like a lot of boys, I’m sure Ian Fleming was an early influence. I’d write Bond knock-offs over the summer holidays, filling exercise books with chapter after chapter of derring-do!

"An English teacher – Mr Harris – indulged my scribbling and pointed me towards Chandler and Hammett, and the whole hard-boiled school. My interest was fired further by a string of adaptations of Chandler on Radio 4, starring the late, great Ed Bishop as Philip Marlowe.

"These days, I try not to miss any of Martin Cruz Smith’s Arkady Renko novels. The late, great Ruth Rendell writing as Barbara Vine was and remains another favourite. I don’t know if you’d class it as crime, but the early Len Deighton novels featuring the nameless hero, upon which the Michael Caine movies were based, have owned my heart ever since I first read them in my teens."

Just as he's quick to pay tribute to the many writers to inspire him along the way, Lewis was happy to include in Endeavour regular cameos from Colin Dexter, who created the character of Morse. Dexter died at his home in Oxford in 2017.

But what's next for Lewis? "Adapting Peter James’s Roy Grace novels for an ITV series starring John Simm as the eponymous hero. They’re contemporary and set in Brighton, which, like Oxford, is very photogenic. I’d say they're thrillers rather than whodunnits – though each is also a cracking mystery. Like any writer, there are always other things in development. But, for the moment at least, Oxford’s finest still has a way to go."

And has he always known how the series will end? "Always. I wrote some of it down, just in case..."

The first six series of Endeavour are available to watch now on BritBox – check out what else is on with our TV Guide