Sir Ian McKellen, who is fronting an advertising campaign for the Albert Kennedy Trust on gay teenagers kicked out of home for coming out, has explained in an interview for The Times why he never came out to his own parents.

The advertising campaign shows Sir Ian sleeping rough while a gang of aggressive yobs douse him in cider.

In the advertisement, Sir Ian says: “Perfectly ordinary loving parents faced with the knowledge that their child is gay are appalled and can’t believe it. If they’re a member of a society or a faith that disapproves of homosexuality, sometimes the first gay person in their life turns out to be their child. They can’t cope. The instant reaction is: ‘Get out of our house’. And you’ve got a child who is homeless simply because he or she told the truth.”

Sir Ian explained to The Times why he never came out to his father (his mother died when he was just 12): “I first accepted I was gay when I was about 16 and I wasn’t attracted to girls in the way that my friends were. I had this secret and there was nothing I could do about it because, as far as I knew, I was the only person.” In reality, Sir Ian’s two best friends were also hiding that they were gay and it wasn’t until 20 years later that they discovered the truth.

Sir Ian’s widower father, Denis, an engineer and lay preacher died when Sir Ian was 24.

“He was a good, good man — a Christian, but not the sort of Christianity that would have condemned it. Well, I was living with a man at the time, so he couldn’t have been surprised. I hope he’d have given me a hug and said ‘That’s fine by me’. But who knows? We didn’t always talk about important emotional matters in my family.

“There was nothing positive about homosexuality in the newspapers and it was against the law to make love. I knew people my age who’d been sent to prison for doing it! When I tell schoolchildren that, they can’t believe it.

“So there was a lot of bewilderment inside me. Why did I feel like this when society said what I was doing was illegal?”

Sir Ian explained how despite being in a gay relationship while a relatively young actor, he wasn’t asked about his sexuality: ” I wasn’t one of those closeted actors who lied about it, but I avoided talking about it. It was easy. Nobody ever asked me. If I had told someone I was gay in an interview, the lawyer would have taken it out anyway because it was considered a terrible thing to say about anyone. Simon Callow would talk about being gay in interviews but it would never be reported. In the end he had to write a book to come out!”

Sir Ian eventually came out to his stepmother and sister and outed himself aged 49, during a radio debate with a right-wing commentator over the introduction of the hated Section 28 legislation that prohibited the ‘promotion’ of homosexuality by local authorities or schools. “It was a very nasty bit of legislation. I joined the campaign against it and realised that I couldn’t talk about it without explaining why I was involved.”