Back to the Future creator explains why franchise will never get a fourth film

The pair had a clause written into their contracts stating that another instalment in the franchise would need their permission to go ahead, and Gale said that studio bosses have made repeated attempts to persuade them on the merits of a fourth film.

When asked about it, Gale said, "All the time. All the time. 'What can we do to convince you guys [Gale and Zemeckis] to do this?'

"We said, 'Nothing'. 'You'll make a lot of money.' 'We already made a lot of money.'

"You know, you don't sell your kids into prostitution. It was the wrong thing to do. We put 'The End' at the end of part three."

He added, "Plus Michael J Fox isn't in the shape to do a movie, and nobody wants to see Marty McFly having Parkinson's disease, and nobody wants to see another actor playing Marty McFly if it's supposed to be a continuation."

With no new film forthcoming, Gale has instead turned his attention to a new stage musical version of the original film – which will have its world premiere at Manchester Opera House this week after first being touted by Gale as long ago as 2004.

Gale said that the musical version was the perfect way of returning to the story without damaging its legacy.

He explained, "We learn from the fact that so many studios have gone back to the well on some of their franchise properties too many times, and the audiences are disappointed and say, 'Oh my God, they ruined my childhood.'

"We don't want to ruin anybody's childhood, and doing a musical was the perfect way to give the public more Back to the Future without messing up what has gone before."