When Back to the Future Part III hit cinemas in 1990, co-creators Robert Zemeckis (director) and Bob Gale (producer and screenwriter) were adamant that there would be no Back to the Future 4.

The two Bobs felt that they had completed the time-travelling adventures of Doc Brown and Marty McFly and have resisted big pay days over the decades to green-light further sequels.

In fact, Gale has joked over the years that it won’t be long before Back to the Future is the only movie trilogy left as…