Fans of Doctor Who were almost left without their favourite show when David Tennant quit, showrunner Steven Moffat has said.

The Scottish actor, 43, departed the sci-fi drama in 2009 after first joining four years earlier. He helped take Doctor Who to new heights by establishing a dedicated following, leading BBC producers to doubt the series’ future once he left.

“David owned that role in a spectacular way, he gave it an all-new cheeky, sexy performance and became a national treasure,” Moffat told the Hay Literary Festival.

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“He didn’t do it instantly, he did it over time. So the idea that Doctor Who could go on at all in the absence of David was a huge question.”

Moffat revealed his suspicion that there were “plans maybe to consider ending it”, noting that Russell T Davies, who led the show’s 2005 revival, was the driving force behind its continuation.

“I didn’t realise how many people though it wouldn’t succeed at all,” Moffat added. “That was quite terrifying when I found out about it later.”

Shape Created with Sketch. Doctor Who villains Show all 20 left Created with Sketch. right Created with Sketch. Shape Created with Sketch. Doctor Who villains 1/20 Doctor Who villains The Daleks: The Doctor’s ultimate foe. They first appeared in the ‘The Daleks’ in the second-ever ‘Doctor Who’ serial back in 1963 and they have been terrorising the universe ever since. BBC 2/20 Doctor Who villains Sil: A disgusting slug-fish-like creature who first appeared in 'Vengeance on Varos'. More repulsive than scary and play brilliantly by Nabil Shaban. BBC 3/20 Doctor Who villains The Silence: A new villain who are forgotten the instant someone looks away from them which makes them quite frightening when they pop up BBC 4/20 Doctor Who villains Sontarans: The giant-looking potatoes have been brought back in the new series and look a lot more high tech than in the classic series. This image is from ‘The Sontaran Experiment’ from the Tom Baker era. The rubber masks left a lot to be desired and we rather embarrassing when the actor would poke his tongue through the mouth hole in the mask. BBC 5/20 Doctor Who villains The Clockwork Droids: Terrifying killer robots that have been known to hide under beds, they featured in the episode 'The Girl in the Fireplace' BBC 6/20 Doctor Who villains The Cybermen: Another prolific ‘Doctor Who’ villain, they have gone through many changes in appearance over the past half a century. This is a still from ‘Tomb of the Cybermen’, a story from Patrick Trougton’s era as the second Doctor. BBC 7/20 Doctor Who villains Autons: Essentially live-sized plastic dummies animated by the Nestene Consciousness. This still is from 'Spearhead in Space' when the Autons made their 'Doctor Who' debut BBC 8/20 Doctor Who villains The Dinosaurs: Okay, not really a villain. They are just doing what dinosaurs do, i.e. hunting prey but worth a mention. This is a still from 'Invasion of the Dinosaurs' which saw prehistoric mysteriously turning up in London BBC 9/20 Doctor Who villains The Master: A rival Time Lord to the Doctor. He too has had many incarnations, most recently played by John Simm (pictured) BBC 10/20 Doctor Who villains The Rani: An evil Time Lady who forced the Doctor to regenerate played by Kate O'Mara. She has yet to make an appearance in the new series BBC 11/20 Doctor Who villains The Weeping Angels: The most frightening modern 'Doctor Who' villain. Known as the 'Lonely Assassins', they only move when you are not looking them. Don't blink BBC 12/20 Doctor Who villains The Zygons: These aliens can shape shift and are slated to make an appearance in 'The Day of the Doctor' BBC 13/20 Doctor Who villains The Cheetah People: They made an appearance in the last serial of 'Doctor Who' before the show was cancelled in 1989. They look like they should be extras on a live-action version of 'The ThunderCats' BBC 14/20 Doctor Who villains The Ice Warriors: This year saw the return of this classic ‘Doctor Who’ villain in ‘Cold War’. They were the second Doctor’s arch enemy and are from Mars BBC 15/20 Doctor Who villains Drashigs: These hideous-looking things were in 'Carnival of Monsters', they are snake-like creatures with six eyes and rather toothy. They are not particularly scary but make a horrible sound BBC 16/20 Doctor Who villains Davros: The creator of the Daleks and is reminiscent of Doctor Strangelove from the film by Stanley Kubrick BBC 17/20 Doctor Who villains Omega: One of the founders of the Time Lord society, he went mad and nearly destroyed the entire universe until he was stopped by the Doctor BBC 18/20 Doctor Who villains The Fish people: They were originally human but had been altered surgically to be able to breathe underwater. They were in a 'lost' story called 'The Underwater Menace' BBC 19/20 Doctor Who villains Scaroth: The last of the Jagaroth who tried to bring his race back from extinction. Julian Glover played Scaroth in 'City of Death', unfortunately his nose could be seen through the rubber mask BBC 20/20 Doctor Who villains The Zarbi: They resemble giant ants with human legs. Read: cheap costumes. These creatures were controlled by an omnipresent life form known as the Animus. This is a still from 'The Web Planet' where the Tardis was dragged onto the Zarbi's planet of Vortis. BBC 1/20 Doctor Who villains The Daleks: The Doctor’s ultimate foe. They first appeared in the ‘The Daleks’ in the second-ever ‘Doctor Who’ serial back in 1963 and they have been terrorising the universe ever since. BBC 2/20 Doctor Who villains Sil: A disgusting slug-fish-like creature who first appeared in 'Vengeance on Varos'. More repulsive than scary and play brilliantly by Nabil Shaban. BBC 3/20 Doctor Who villains The Silence: A new villain who are forgotten the instant someone looks away from them which makes them quite frightening when they pop up BBC 4/20 Doctor Who villains Sontarans: The giant-looking potatoes have been brought back in the new series and look a lot more high tech than in the classic series. This image is from ‘The Sontaran Experiment’ from the Tom Baker era. The rubber masks left a lot to be desired and we rather embarrassing when the actor would poke his tongue through the mouth hole in the mask. BBC 5/20 Doctor Who villains The Clockwork Droids: Terrifying killer robots that have been known to hide under beds, they featured in the episode 'The Girl in the Fireplace' BBC 6/20 Doctor Who villains The Cybermen: Another prolific ‘Doctor Who’ villain, they have gone through many changes in appearance over the past half a century. This is a still from ‘Tomb of the Cybermen’, a story from Patrick Trougton’s era as the second Doctor. BBC 7/20 Doctor Who villains Autons: Essentially live-sized plastic dummies animated by the Nestene Consciousness. This still is from 'Spearhead in Space' when the Autons made their 'Doctor Who' debut BBC 8/20 Doctor Who villains The Dinosaurs: Okay, not really a villain. They are just doing what dinosaurs do, i.e. hunting prey but worth a mention. This is a still from 'Invasion of the Dinosaurs' which saw prehistoric mysteriously turning up in London BBC 9/20 Doctor Who villains The Master: A rival Time Lord to the Doctor. He too has had many incarnations, most recently played by John Simm (pictured) BBC 10/20 Doctor Who villains The Rani: An evil Time Lady who forced the Doctor to regenerate played by Kate O'Mara. She has yet to make an appearance in the new series BBC 11/20 Doctor Who villains The Weeping Angels: The most frightening modern 'Doctor Who' villain. Known as the 'Lonely Assassins', they only move when you are not looking them. Don't blink BBC 12/20 Doctor Who villains The Zygons: These aliens can shape shift and are slated to make an appearance in 'The Day of the Doctor' BBC 13/20 Doctor Who villains The Cheetah People: They made an appearance in the last serial of 'Doctor Who' before the show was cancelled in 1989. They look like they should be extras on a live-action version of 'The ThunderCats' BBC 14/20 Doctor Who villains The Ice Warriors: This year saw the return of this classic ‘Doctor Who’ villain in ‘Cold War’. They were the second Doctor’s arch enemy and are from Mars BBC 15/20 Doctor Who villains Drashigs: These hideous-looking things were in 'Carnival of Monsters', they are snake-like creatures with six eyes and rather toothy. They are not particularly scary but make a horrible sound BBC 16/20 Doctor Who villains Davros: The creator of the Daleks and is reminiscent of Doctor Strangelove from the film by Stanley Kubrick BBC 17/20 Doctor Who villains Omega: One of the founders of the Time Lord society, he went mad and nearly destroyed the entire universe until he was stopped by the Doctor BBC 18/20 Doctor Who villains The Fish people: They were originally human but had been altered surgically to be able to breathe underwater. They were in a 'lost' story called 'The Underwater Menace' BBC 19/20 Doctor Who villains Scaroth: The last of the Jagaroth who tried to bring his race back from extinction. Julian Glover played Scaroth in 'City of Death', unfortunately his nose could be seen through the rubber mask BBC 20/20 Doctor Who villains The Zarbi: They resemble giant ants with human legs. Read: cheap costumes. These creatures were controlled by an omnipresent life form known as the Animus. This is a still from 'The Web Planet' where the Tardis was dragged onto the Zarbi's planet of Vortis. BBC

Clearly Davies’ insistence that Doctor Who cast a new lead under Moffat’s tenure proved fruitful. Matt Smith took over from Tennant to be welcomed by fans and soon, Peter Capaldi will take the Time Lord’s reins for the eighth series.

Doctors past and present reunited for 50th anniversary special The Day of the Doctor last year, which picked up the Radio Times Audience Award at the Bafta TV Awards earlier this month.