• Meet the cast of Endeavour series five
• Endeavour fans think Shaun Evans is becoming more like John Thaw’s Morse in series five
• Endeavour will return for a sixth series, but some cast members won’t be back

Warning - spoilers ahead

You see, the latest episode also included the shock death of Lewis Peek's DC George Fancy, a new character introduced this year who was apparently caught in the crossfire of a gang war in the latter half of the story. After his death, Cowley police station was shuttered and the team found themselves headed to separate postings, while WPC Trewlove (Dakota Blue Richards) went off to pastures new and DCI Fred Thursday (Roger Allam) was forced to put off his retirement.

So what's next for the series? The new set of feature length films will be set in 1969, and will be be filmed later this year ready for a release in 2019.

"As our story reaches the last year of the 1960s, and mankind makes its giant leap, all at #TeamEndeavour look forward to exploring further early chapters in the casebook of Colin Dexter’s beloved creation,” creator Russell Lewis teased.

To find out more, we caught up with Endeavour's executive producer Damien Timmer, who revealed that DC Fancy was doomed from the start, how real-life historical events influenced writer Russell Lewis' finale, and exactly what we can expect for the newly-announced sixth series of the drama.

Spoiler alert: the times, they are a-changin'.

Hi Damien - there's a bit of a shake up at the end of this series, with characters moving to different places. What was the thinking behind that?

Because of the real life change in 1968 with the birth of Thames Valley Police, it felt creatively like a good time to challenge our characters and have them leave their police home. More pragmatically, we have had to leave our production base in Beaconsfield, and this is a chance for a new studio build in a new home.

Russell Lewis enjoyed the idea of shaking it up, as you put it, because the dynamic between Endeavour, Thursday, Bright, Strange, has been set since series one. Now, five series into it, we rather enjoyed the fact that history forced us into a change in the dynamic.

Did it need a refresh?

In a very positive way, Russell takes our 1960s timeline very seriously, and since the pilot he has enjoyed locating particular Endeavour seasons and individual Endeavour stories very clearly in a particular time. So, for example, in series three, there was a story called Prey which was set in the time of the Six-Day War.

In series five we have enjoyed glancing to real historical events - the assassination of Martin Luther King, for example, kind of informs one of the stories. We think it just gives it another layer.

We've known for years, in truth, at some point that we'd have to leave the world of Oxford City police. We've rather enjoyed throwing things up in the air.

So as the characters move to new stations, could it lead to us seeing some more modern policing techniques in any future series?

Yes, I think it absolutely would.

How would the characters we've grown to know and love still interact if they're all working in different stations? Will we be meeting a lot of new characters?

You'll have to wait and see! It throws everything up in the air. And I suppose things land, pieces land in strange situations. And it might take some time to sort things out, and it's possible that things are never quite the same again.

We've really enjoyed spending quite a few years of the 1960s with that sort of police family, and seeing Endeavour develop in that, when in series one he is very much an outsider. Superintendent Bright, played by Anton Lesser, is incredibly suspicious of him. He's a very isolated figure.

And by the time you leave series five, he's much more accepted by that group, and they have become a real police family. It feels interesting to put them all under this new pressure.

Thursday seems to be retiring for most of the series, which had me pessimistically assuming he was going to die! Was there an attempt to lead the audience in that direction?

Well, part of his arc for the series was Thursday coming to a point where it feels to him that the old order is changing. And for Win, his wife, this sense of emotional retirement is quite appealing. And it's set up pretty early on in the series that his ne'er-do-well brother borrows money from him, and it was always there in Russell's mind that that wasn't going to work out, and be one of the factors that makes it difficult for Thursday to leave.

And one of the things that the show has always been preoccupied with is the world changing around our heroes, and I think that's very appropriate when dealing with a character like Thursday who has spent a very long time, has grown up in that Oxford City police force, and feels that perhaps this is time for him to take his leave. But events conspire against him.

I don't think that's tricking the audience. I think that's just, hopefully, a pleasing story.

Of course, the death of DC George Fancy is one of the big shocks of the episode - was it always intended that he'd have that one-season arc?

It was! Unfortunately for the very talented Lewis Peek, who plays him, yes, he was dead before he was written. Because we had six films this year, we knew we had a little bit more time to explore the different character dynamics.

The feeling was we'd spent a lot of time seeing Endeavour as Thursday's protégé, but that in a way that perhaps prefigures Inspector Morse, it was interesting to see Endeavour, since his promotion, play the part of a mentor himself.

We liked the idea of a relationship with a young protégé that begins badly, then gets a little bit better but not very much better – Endeavour and Fancy were never a great love match. But that ended in tragedy. That was always Russell's design.

The final scenes of the episode suggest that the hunt for whoever killed him is the arc for the next series - is that the idea?

It's certainly something that will preoccupy the characters, yes.

On a similar topic, is this the last we'll see of WPC Trewlove, as played by Dakota Blue Richards? She heads off to join Scotland Yard in the finale

This is the end of Trewlove for now – Dakota told us she wanted to leave at the beginning of last year, so we planned series five to give her the arc with Fancy and build to his demise and her leaving. But the door is always open for return appearances!

For the next series, would you like to have another long six-episode run like you did this year, as opposed to the usual four?

It's a punishing thing, doing six films, because Russell Lewis writes every word. And writing 12 hours of new material is a really serious undertaking. It was never seen as becoming the norm, is my slightly obtuse answer.

Some fans thought Endeavour was more like John Thaw’s Morse this series – was there an attempt to bridge the gap?

I noticed that people seemed to feel that in various films. We've now made I think 23 films including the pilot, and across those we've wanted to show incrementally how the character could go from being this relatively fresh-faced young policeman to the character who we all know and love as John Thaw's Inspector Morse.

Were you to sit down and watch them all, I think you'd see a subtle yet certain gentle transformation there. He has become more forthright, or the people around him listen to him slightly more. He has become a little bit more sure of himself, and is perhaps quicker to anger than he originally was. But I think that's been a creeping thing across the series.

I think perhaps we felt it more this year because we've had six films instead of four.

In classic episode Masonic Mysteries, Morse said his mentor was Inspector McNutt - is that a character we could see in Endeavour?

Well, we already know McNutt’s fate from the Inspector Morse story Masonic Mysteries. With DCI Thursday, only Russell Lewis knows what happens to him – which I think raises the stakes in our Endeavour story. We know Morse’s fate, but we have to keep watching to find out Fred’s!

Russell didn't want to have McNutt at the beginning, because he had a very strong sense of Fred Thursday and the Thursday family. We absolutely love Fred Thursday, we love Roger Allam as Fred Thursday, Roger Allam enjoys playing him and I think the audience would now be incredibly shortchanged if Fred were to go and McNutt were to enter.

That's not to say that we won't at some point meet Inspector McNutt - he has been mentioned onscreen hitherto, but he has not yet appeared.

Looking forward, could you do any other Morse spin-offs, say about Laurence Fox’s Hathaway from Lewis?

Hathaway was an extremely popular character! But we have truly, genuinely found the world of Endeavour that Colin Dexter showed us and which Russell has taken so much ownership of, has really kept us very creatively fulfilled. And we're so happy being in that world for now.

23 films in, we're still finding that very stimulating and we have no plans for anything like that. Endeavour is where our focus is.

And finally – could you give us the inside scoop on all those clever references hidden away in Russell’s scripts every week?

Russ enjoys sneaking in pop culture refs into his scripts, ranging from Kate Bush lyrics to Terry Pratchett. Some of them we spot, others only become evident on transmission.

I love Chinatown, but hadn’t noticed where Thursday’s “Forget it sergeant, that’s Summertown” line came from until Twitter told me on transmission!

Endeavour will return for a sixth series