“I don’t think any of us realised the scope that Netflix brings - being on the platform and being available around the world immediately for anyone to watch on their phone or their TV,” he told the RTS.   

“It’s insane. I’d worked in film where there’s a build up to the release date, but to have it all there at the touch of your fingers was quite surreal.   

“Then to have it amplified by social media. I’d experienced some of that in my (previous film) work, but for some of the cast going from very little public exposure to being one of the most watched shows on Netflix was insane.”  

In Sex Education Butterfield, who is 23, is cast as the son of sex therapist, Jean Milburn, played by Gillian Anderson.      

He said: “It was a privilege to have Gillian Anderson play my mum.   

“Funnily enough, my actual mum is a psychologist, not a sex therapist but in a similar vein of questioning and quite cerebral. Me and Gillian have a lot of fun.   

“We found this really nice rhythm to the mother and son relationship which sometimes is quite mature and civilised, but at other times they can both be so immature.   

“It’s quite a volatile relationship. There are some very touching scenes and very funny scenes.”    

When he accepted the part of Otis, who as the story progresses becomes a reluctant sex therapist at his school, he wasn’t sure Sex Education would be a hit “because of the way it pushes at boundaries,” by virtue of its sexual content.   

“For me as someone who’s not done much comedy, not much sexual comedy, to push myself on screen was fun,” he explained.    

“I’m always looking for projects that are going to test me.”  

Regarding the sex in Sex Education Butterfield noted: “I feel that these days young people are growing up quicker and exposed to a lot.   

“It makes sense to treat them with maturity because of the knowledge that everyone has at the tips of their fingers. You don’t need to shy away from it.”  

Season two famously opens with a montage of Otis masturbating in various locations, including his bedroom and a car park.    

“People appreciated how honest and frank the show was,” he said. “It bolstered our love for it because we believed in it and we loved making it.”  

Watching the show helped people to feel less alone in their “own weirdness” - although he conceded that watching the masturbating sequence alongside his mother was “embarrassing.”   

Butterfield, now putting the finished touches to series three of Sex Education, started acting aged seven. He revealed that he did not consider acting as a career until he starred in Martin Scorsese’s Hugo, released in 2011.  

The director told him about cinema history giving him films to watch at the weekend.   

He recalled: “It was the ultimate education. That captured my imagination and made me think maybe I could do this as an adult.”  

One reason Butterfield was attracted to Sex Education was because he wanted to be involved in a returning TV series that expanded his acting ability. 

Another factor was the end of the classic film and TV divide, with US cable channels and then streaming services pouring millions of dollars into scripted shows.   

Apart from Hugo, Butterfield's film roles have included Greed, which starred Steve Coogan, and the holocaust movie, The Boy In the Striped Pyjamas.   

Butterfield was a child when he made The Boy In The Striped Pyjamas. How much was he aware of the darkness of the subject matter?  

 “It was almost 15 years ago. I remember reading the book before we started shooting so I did have some understanding of World War Two and some of the things that went on, but when we made it, they did try and preserve my innocence.   

“As a nine-year old that made sense for my mental health. I do remember some of the scenes being quite difficult.”       

Fantasy, horror and westerns are all genres he would like to work in in the future.   

As for who he’d like to work with Butterfield singled out actors Leonardo DiCaprio and Ian McKellen, and director Peter Jackson.  

Asa Butterfield was in conversation with broadcaster and journalist Caroline Frost at an RTS event on January 19.