Experience: I’ve been on television more than 2,500 times (but you won’t know my face)

‘She was cast as my wife. I told her I’d marry her for real’: John Walker with his wife Neilum and daughter India. Photograph: Stephen Burke/The Guardian

I have always been a television addict. As a young boy growing up in Bath, I’d devour programmes such as Doctor Who, desperate to know how they were created. At 16, I dared to tell a school careers adviser that I wanted to work in TV; she laughed and said a career in television was for people who went to university. She suggested I get a job in retail. Dejected, I reluctantly took on a job at a supermarket, but made my way up through the ranks. They had a budget for making corporate films, and I ended up directing and producing their training videos.

Then, in 1998, I saw an advert in a sci-fi magazine for unpaid extras for Auton, a Doctor Who spin-off. I dashed off an application and was thrilled to get a call weeks later, offering me a role as a villager.