On paper, a musical comedy about a mad transvestite scientist does not sound like a hit, certainly not one that has continuously packed theatres for more than 40 years.

Even The Rocky Horror Show’s writer Richard O’Brien is astonished by his evergreen creation, which was originally due to run for just two weeks when it debuted at the tiny 42-seat theatre upstairs at the Royal Court in 1973.

Speaking ahead of its performance at Dartford’s Orchard Theatre from June 6 to 11, O’Brien told us: “It just kept surprising us. It ran for seven years on that original run, which was astonishing.

“It just doesn’t want to go away. It is a phenomenon. There is no doubt about it, because it doesn’t have the ingredients one would expect to give it this much longevity.”

In fact, the show is perhaps as strong now as ever. Last summer, to celebrate the 40th birthday of its film sibling The Rocky Horror Picture Show, a two week residency was held at the Playhouse Theatre which included a star-studded gala performance for Amnesty International which was beamed live to 600 cinemas across the country.

Even though it was a one-off screening, it still took the number one spot at the UK box office ahead of Tom Hardy’s Kray twins film Legend.

Certainly part of the Rocky Horror Show’s appeal is its naughtiness, but O’Brien believes something more traditional resonates with audiences.

He said: “When we released the movie, I think we had on the poster we had ‘something for everyone’ and there is a truth in that. It is a fairytale, you see.

“That has probably got something to do with its longevity. There is a recognition, a note which is struck that chimes somewhere in people.

“It is the story of the fall, Adam and Eve – Frank N Furter as the serpent – or Hansel and Gretel – Frank N Furter as the witch.

“All those things add up in its favour and turn it into something that we all have a deep seated recognition of somehow. There is a familiarity about it which is enjoyable.”

He added: “Fairytales are generally about rites of passage, which once again is Rocky. When they start out they are a confirmed heterosexual engaged couple, a Republican couple I would say, and here they are after this night where they have both been to bed with this creature Frank N Furter and their lives are completely changed.

“They will never be able to undo that.”

Whatever its appeal, The Rocky Horror Show is virtually unique in the crowds it attracts too. It is a notoriously enjoyable show to watch, with fans dressing up and a healthy dose of audience participation.

For former Crystal Maze host O'Brien, it is important that was an organic decision by spectators and not something pre-planned by producers.

He said: “Part of its charm is that we didn’t go out looking for that audience. That audience came to us.

“If you attempted to organise that yourself and turn it into a cult knowingly, I would be resistant as a potential audience member because I wouldn’t want to feel like I was being manipulated.”

The Rocky Horror Show is at the Orchard Theatre, Dartford, from June 6 to 11. Go to orchardtheatre.co.uk or call 01322 220000.

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