RICHARD O’Brien is missing the 40th anniversary tour of his cult rock’n’roll musical, The Rocky Horror Show, but for the very best of reasons.

“My fiancée and I are going out to New Zealand to become wedded and set up shop there,” says Richard, who will turn 71 on Monday. “I’ve been planning to settle there for a long time.”

The show will go on, of course, in Christopher Luscombe’s All New 40th Anniversary Party production, which visits York next month for a week-long run at the Grand Opera House with a cast led by Oliver Thornton as scandalous Frank N Furter and former Emmerdale soap star Roxanne Pallet as squeaky clean Janet.

Richard’s departure to New Zealand is not a bolt out of the blue. Although he was born in Cheltenham – severely premature, on March 25, 1942 – he first moved to the other side of the world at the age of ten.

“I wasn’t meant to survive the night I was born, and here we were in the war and all that, but ten years later my family decided to go to New Zealand. I’m not sure why,” he recalls. “But I was delighted; I was ten and we were leaving monochromatic, stuffy British society to go to this Technicolor, classless society with no-one behaving like they were your superior.”

When he returned to Britain, ostensibly it was “only for a year’s working holiday”. “I was at a loose end; I was 22 years of age and I was lost, so I came to England and life took over,” says Richard.

He immediately noted the contrast with New Zealand. “In Britain, everyone had to suffer those attitudes of class, but having been brought up in New Zealand, I found I could sit with anyone; I had access to all areas,” he says.

In turn this led to the ultimate outsiders’ musical, The Rocky Horror Show, a shock to the conservative system with its fishnet fun and frolics.

Now New Zealand is calling him once more. “I’m going to live on the North Island; it’s where we ended up when we deposited ourselves, at the Bay of Plenty. It’s where my parents are buried and my brother and sister still live there,” he says.

Richard has no qualms about the future of The Rocky Horror Show. “I have responsible, good, capable people around me,” he says.

“We formed a company called The Rocky Horror Company about 20 years ago so that we could oversee the licensing of the show.

“We forged a link with producer Howard Panter (whose company, the Ambassador Theatre Group, owns the Grand Opera House), which meant we could put in some safety barriers so that we can cushion ourselves; have an overview of things; perhaps have a say on casting, to make sure the audience gets the best show we can give them.”

The Rocky Horror Show, with its transvestism and pelvic-thrusting Time Warp dance moves, retains its cult status, still being called “the boldest bash of them all” in its publicity.

“It retains that badge when it’s quite positively mainstream now. It’s difficult to understand why, but it seems to maintain those cult credentials and that pleases me,” says Richard.

He was inspired originally by “the kind of theatre coming out of New York” in the Sixties.

“It was loose and hippy driven and there was a kind of joy in what they were doing. Hair captured some of that feeling, and the original version of Jesus Christ Superstar had that feeling too,” he says. “When we first did The Rocky Horror Show, there was still that ensemble joy in the piece.”

The sense of liberation that once surrounded Rocky Horror is now making way for our age of health and safety: no rice can be thrown on stage; lit-up mobile phones must replace the glow of a lighter’s naked flame. I think safety issues are a boring kind of idea – you can’t have children’s playgrounds anymore – but I don’t think there’s a way around it,” says Richard.

“Maybe it’s the theatre owners saying it would be nicer if they didn’t have to clear up the rice.”

The Rocky Horror Show’s popularity, nevertheless, survives any such rules and regulations. “I’ve tried to divine the longevity of this show, its continuing attraction,” says Richard. “It’s a camp piece of juvenilia that skates along, on the surface, but if that was all it was, it wouldn’t have survived.

“It harks back to the traditional fairytale journey; sweethearts Brad and Janet are Hansel and Gretel or Adam and Eve, and that all ties in with this musical without directly saying so.

“You have no idea why people enjoy these fairytales because the message is not that obvious and yet children enjoy them and have done for centuries. They get into the subconscious and Rocky Horror does the same thing – or that’s my guess.”

Such has been the impact of The Rocky Horror Show that it has been chosen at the V & A, in London, as one of the ten most important pieces of British theatre since 1945. In May, Richard will receive an honorary doctorate at the University of Waikato in Hamilton. “I may not be the brightest, but I did create this show,” he says.

What will the flamboyant Richard wear at the ceremony? “A gown and cap, of course,” he says.

• Richard O’Brien’s Rocky Horror Show takes over the Grand Opera House, York, from April 8 to 13; Monday to Thursday, 8pm; Friday and Saturday, 5.30pm and 8.30pm. Box office: 0844 871 3024 or atgtickets.com/york

• Did you know?

Richard O’Brien’s real name is Richard Timothy Smith.