Modern blockbuster film-making is calling out for a new The Fifth Element, but Valerian and the City of a Thousand Planets isn’t it. Two decades after Luc Besson’s classically garish retro-future space opera, he’s returned to the same aesthetic; it’s another summer film based on a comic book, sure, but not what you would expect. Valerian is based on the French comic series Valérian and Laureline, written by Pierre Christin and illustrated by Jean-Claude Mézières, which began its run in the pre-Star Wars sixties. Besson, a long-time fan of the series, obviously drew on it for 1997’s weirdo favourite, and…