A Doctor Who legend has issued a major complaint about the iconic BBC series as he said he was ‘terribly worried’ in an admission. It's been a turbulent period for the programme , with fans unsure when they’ll next get to witness further space adventures with the Timelord. Last month saw popular lead actor Ncuti Gatwa unexpectedly leave the show after just two seasons playing the titular role. The Sex Education actor's tenure as the 15th Doctor came to an end as he regenerated into Billie Piper, who previously played Rose Tyler on the programme. Adding to the confusion of the moment was that Billie was not credited as The Doctor in the credits, with the cliffhanger unlikely to be resolved for a number of years. With Doctor Who fans continuing to speculate what will happen next, Peter Davison has criticised Doctor Who for relying too much on special effects. The 74-year-old actor, who was the Fifth Doctor from 1982 to 1984, fears the programme has relied too much on pushing for constant action, which has left ‘huge gaps in the narrative’ of the show. Speaking on The Lewis Nicholls Show, he said: "As the special effects got even better, there's a danger that it becomes just about special effects." Comparing Doctor Who to superhero movies, he added: "They're terribly worried now about people’s attention spans. If something isn’t happening every two minutes, they think people are going to turn off, which I don’t believe is true." Praising modern crime dramas for incorporating a slower pace to tell their stories, he hit out at the sci-fi genre for not doing the same. He explained: "For some reason, in science fiction, they feel like they need to go at 100 miles per hour and that makes it, to me, like trailer television. "There are huge gaps in the narrative because they're just leaping onto the next bit and your brain is meant to fill in the [gaps]. "Maybe if you're young and healthy, you can do that, I don't know. I just find it almost like you're watching a trailer for a Doctor Who show you'd like to watch later." Despite his issues with Doctor Who, Peter commended showrunner Russell T. Davies for ‘curing’ problems including giving previously underused ‘great characters’ things to do. Having his say about Billie Piper being back on the show that made her a star, Peter recently told Starburst magazine: "I don’t know what Billie Piper is doing. I have just read about it, and I don’t know what it’s about. It’s a completely mad idea. "I don’t think she is the Doctor. I think it’s kind of just a hand grenade thrown into the final episode to try and go, 'Whoa, what’s this?' And then it’s almost like, 'Get out of that’. "I thought she was a fantastic companion, but she’s got a great career, and she’s got options galore. I don’t know why she would voluntarily choose to go back to Cardiff for a year."