Merlin co-creator looks back, 15 years on: 'We talk a lot about exploring the legend again'

"The show was commissioned at the beginning of the year and we had to deliver it in September. We were like, 'Yeah, we can do it' – because you're not gonna say you can't do it, but we got to a point where Merlin was transmitting, and we were still filming it.

"Julian [Murphy, series co-creator] and I are going, 'My God, do we have to apologise to the nation if we can't get this episode ready in time?'

"There was one time where episode 13 failed a technical test. We had to take it back on the Friday evening, sort out the technical problems, and it was almost literally me on a motorbike, holding the tape, rushing into the BBC and putting it into the machine."

Though it might have included the odd stressful moment, Capps tells RadioTimes.com that he has "hugely fond memories" of his time spent working on Merlin, which premiered 15 years ago today, transmitting its first episode on BBC One on Saturday, 20th September 2008.

Along with Julian Murphy, Capps had previously founded Shine Drama to develop series for television – the pair, along with writer Jake Michie, were big fans of Smallville, the US drama charting Superman's teenage years, and decided to try developing a fantasy show with a similar slant for a family slot.

Delving into the various Arthurian legends, Capps says he and his co-writers were "like magpies", picking their favourite parts from Cornish, Welsh, Scottish and Irish traditions. "The myth is so fascinating and so rich, so we looked at all of those things and it was always about subverting expectations, twisting all of those legends."

Though Smallville was very much "the blueprint" for the series, another more unlikely source of inspiration also shaped the style and tone of Merlin. "For us, humour was really important, The cheekiness of it. We talked a lot about Shrek and how Shrek worked on lots of different levels, so parents loved it and young people loved it. It was about finding that slightly knowing humour, playing with the legend and having a little bit of fun with it."

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With a draft script in hand, following a teenage Merlin who resides in a kingdom where magic is outlawed, the team began conversations with Julie Gardner, then Head of Drama for BBC Wales, who in turn encouraged them to speak with Russell T Davies, the once and future showrunner of Doctor Who.

"Julie Gardner and Russell T Davies really helped us be bold with our vision of making it [like] Smallville and doing the origin story of not only Merlin, but Arthur, Guinevere and Morgana and all of those legends," Capps recalls. "They really helped us massively to hone the format of the show."

The success of Davies's revived Doctor Who also had a significant impact in securing Merlin the green light, Capps believes. "I think it had a huge effect, Russell had turned around the fortunes of Doctor Who, it was doing unbelievably well. At that time, family viewing really worked, something that wrapped round Strictly, and so absolutely the huge success of those two shows gave the BBC the confidence to go for another family show."

With the series commissioned, the next major challenge was casting the show's four young leads – a process that Capps describes as "really, really hard but really, really good fun".

"We worked with Jill Trevellick, who is the most brilliant casting director. I remember in the first weeks, Jill would say, 'Johnny, I just don't think I can do this. I don't know if I can find these people,' because we had such a specific idea in our head of what we wanted. But, you know, testament to Jill, she found us brilliant people."

Bradley James was first choice to play Prince Arthur, having previously worked with Capps and Murphy on the 2008 BBC TV movie Dis/Connected. "He had all the qualities that we wanted in Arthur – Brad is a fantastic actor, but also he's brilliant at comedy, and we wanted a Jeeves and Wooster feel, where Arthur is 'a hero', but he's not really the hero, the hero is the underdog, Merlin.

"Magic was banned, so Merlin was the secret hero, and Arthur is the Once and Future King, but he's a bit of an idiot. From that, and the fun of that, hundreds of stories came into our minds."

Colin Morgan – a relative newcomer who'd memorably guest-starred in the Doctor Who episode Midnight – was hired to play Merlin, with Angel Coulby cast as Guinevere ("Gwen" to her friends) and Katie McGrath rounding out the regular cast as Morgana.

Matt Smith, two years prior to his Doctor Who debut, was also "hugely high up" the list of potential names to play the show's title character, while his future companion Karen Gillan was in the running to play Guinevere. "We met lots of actors – and lots of them are doing unbelievably well now," says Capps.

"We were really lucky because we got a fantastic cast. All of them were utterly brilliant."

Alongside its fresh talent, Merlin also recruited more seasoned players, including Richard Wilson as Merlin's mentor Gaius and Anthony Head – already a beloved figure in fantasy TV circles after his run on Buffy the Vampire Slayer – as Arthur's ruthless father, King Uther Pendragon.

"It's going on a Saturday night with high expectations and we wanted an unknown cast in the leads – the BBC took a massive leap of faith," says Capps. "So it was important to cast them [Wilson and Head], because I think it gave the show gravitas."

The BBC's faith in Merlin was well-placed – the series was a significant success, scoring solid audience figures and generally positive reviews, as well as developing a hugely passionate fan following. Its tales of magical creatures, supernatural threats, action, romance and derring-do also evolved across its five seasons, with a frothier tone in early outings gradually maturing as the show continued.

"Series one was quite sweet and innocent in the stories we told, but by the last couple of seasons, we were really telling quite dark stories between Merlin and Arthur – quite complex emotional stories, which they [actors Morgan and James] could do," Capps says.

"Colin and Bradley had fantastic on-screen chemistry – they just lit the screen up with their fun and their humour and their brotherly love for each other, so that made us able to write really intense emotional stories between the two of them, as the characters got older and as the stakes of the story got higher in each season. Because they were so good, we could write much richer stories for them."

Fans latched on to the close bond between Merlin and Arthur, with some calling for the relationship to evolve and go down a romantic route – with the benefit of hindsight, knowing the strength of the reaction to the pairing, does Capps think the series should have explored that dynamic?

"No, I don't think so. It was a beautiful friendship and there was a huge amount of love with them, but I don't think you'd want to take that any further. I think there's something very beautiful about a really intense friendship between two people that is non-sexual – that to us was the beauty of it, this extraordinary friendship."

The series hinged on Arthur remaining oblivious to Merlin's magic – though other characters would learn the young wizard's secret across the span of the series, the now-King Arthur would not learn the truth about his friend until the very final episode and there was never any discussion about an earlier reveal.

"As soon as Arthur knows that Merlin has magic, we felt the format of the show was over," Capps explains. "Because the format of the show was that he had to hide it. It's the end of the story – or the end of this version of the story."

Broadcast on Christmas Eve 2012, the final episode of Merlin saw Arthur sustain a fatal wound in battle, the King of Camelot dying in Merlin's arms. But the story of Merlin and Arthur is not quite done – the Great Dragon (voiced by the late John Hurt) tells Merlin that Arthur will rise again in Albion's greatest hour of need.

The show's final scenes see a surprise leap into the present day, with an immortal Merlin still waiting for the Once and Future King to rise again.

"We'd run out of legend, so you couldn't really take it any further," Capps says of the show's final arc. "It just kind of came to us – there was just something really lovely about... he's waiting for the next incarnation of Arthur, there's something sort of sadly beautiful about that."

There was no serious discussion about a sixth season of Merlin – Capps says there was a "roadmap" for the show with the fifth season as its endpoint, while the cast were also only contracted for five years. "Spinning Merlin into modern times was our way of [opening it up] if people after us wanted to do something with it, but for Julian and I and the writers and the actors, we all thought that five series was really good and we were going out on a high note."

There were, however, "quite advanced talks" about a series of Merlin movies, planned to be produced after the drama had wrapped but to feature stories set within the timeline of the television show. "But it all got a bit complicated and then, you know, with these things, they fall apart, but we did very seriously talk about it.

"The idea was to have a trilogy of movies, and the movies were going to happen in-between the series – that was the idea, in those kinds of timelines. It would have been really good fun to do them."

Instead, Capps and Murphy turned their attentions to another fantasy myth – airing in the old Merlin slot, Atlantis was inspired by Greek mythology and lasted for two seasons on BBC One, ending in 2015. It was something of an end of an era, with many other shows produced as part of a post-Doctor Who boom of Saturday night fantasy drama – including the BBC's Robin Hood and ITV's Primeval – having already departed screens.

"Merlin ran for five years, Atlantis ran for two years... that's seven years and audiences change," says Capps. "Netflix came in, and people's viewing habits changed. But would we make more shows for that slot? Absolutely. We talk about it a lot."

Could one of those shows be a Merlin revival? Never say never, according to Capps. "All of that mythology is utterly superb. Julian and I talk a lot about exploring the legend again."

But if we never return to Camelot, or see Merlin and Arthur reunited in the present-day, Capps is satisfied with the show as it stands – though the visual effects might have dated, he believes Merlin's magic has otherwise stood the test of time.

"If we did it again, we would be able to do the effects far better. The dragon at the time was really pushing the boundaries of what you could do on television time and money. You'd be able to do that really differently now.

"But I genuinely don't think we could have cast it better and I'm very proud of the scripts and what we did. We could make it better now, because technology is much better, but in regards to anything else, I don't think I would change it at all."

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Merlin is available to watch now on BBC iPlayer and is also on BritBox – sign up for a 7-day free trial here. The series is also streaming on Sky and Disney Plus.

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