When George Lucas first penned The Adventures of Luke Starkiller, creating a world in which Darth Vadar didn't wear a helmet, R2D2 had actual dialogue, and it wasn't just Jedi who carried lightsabers, little did he know that the Star Wars franchise would go on to become one of the best-loved sagas ever created, making a whopping $30.5bn (£23.7bn) over its 40-year history.

The franchise has become such a behemoth that not even Jar Jar Binks could destroy it, hard as he may have tried. After four decades there is no sign that the world is becoming sick of Star Wars, despite the growing raft of films, cartoons, comics and merchandise bearing the brand.

As of yesterday, the trailer for the upcoming Episode VIII film, The Last Jedi, had 39 million views on YouTube, with more people tuning in for a sneak peek of the galaxy far, far away than for Marvel's Thor: Raganok and DC's Justice League, two similarly anticipated films this winter.

As Disney launches its Force Friday II merchandising blitz today, releasing its new range of Last Jedi clobber, The Telegraph takes a look at the Star Wars films' box offices figures, how much it generates from merchandise sales, and why Disney was right to buy it.