Following the frankly dire closing of the fully-fledged X-Men trilogy, and the downright awful X-Men Origins: Wolverine, the world needed another saga spinning off from Marvel’s flagship franchise like it needed a double-dip recession. Yet in the hands of Brit helmer Matthew Vaughn the series finds itself reinvigorated, imbued with an anarchic tone that – to a point – stands in sharp relief to the righteous indignation and thinly veiled jingoism that make so many superhero movies bland in a way CGI simply can’t mask.

Clearly doing his level best to go rogue any time he felt he could get away with it, X-Men: First Class confirms Vaughn as a major directorial talent, following false starts with both the sorely underrated Stardust and the criminally ignored Kick-Ass. It also serves as the darkest chapter for any on-screen Marvel saga to date, with the unmitigated brutality of Nolan’s Batman movies clearly a touchstone.

Opening as the first X-Men movie did, we find a young Erik Lehnsherr (older, Michael Fassbender) contorting the barbed wire gates of a Polish concentration camp as he sees his mother carted away by the guards. Inside a sinister Nazi scientist, Sebastian Shaw (a wonderfully sneering Kevin Bacon), cruelly torments Erik, drunk on curiosity at this young thing’s dazzling ability. Elsewhere a pint-sized Charles Xavier (older, James McAvoy) finds a curious blue chameleon creature (older, Jennifer Lawrence) raiding his kitchen for food. So-far-so-standard-origin-story. Yet Vaughn has his own mojo working, taking advantage of the picture’s Cold War setting to both lampoon the swinging-sixties, and orchestrate a globetrotting adventure the style of which recalls the very finest in old fashioned espionage serials.

Flashforward a few years and we pick up Erik as a Nazi Hunter, operating with an understated menace and casual sadism that that pushes the PG-13 rating to its very limit. It’s in these earlier, more intimate moments of character that Vaughn’s clever and subtle manipulation of tone really shines. Yes, these are bad people who deserve what’s coming, but in a nod to Erik’s innate darker side both the director and Fassbender ensure the character retains your sympathies while making sure you know that on some level he is enjoying this just a little bit.

Equally impressive is McAvoy, one of the finest actors of his generation, still searching for that breakout mainstream hit. His Xavier is a man more interested in using his powers to get women to go to bed with him than to benefit all of Mutantkind. A deft blend of youthful exuberance, thinly veiled arrogance, and calculated empathy, a neat little combination that allows the actor to add expert comic timing to his already extensive list of attributes. Finally, you have Kevin Bacon, who at one time would never have bothered with such material, but who reportedly lost big in the Madoff affair and now needs a paycheck or three. His Shaw is the kind of diabolical lunatic whose world-ending schemes recall the ambition of early James Bond. And as another of Vaughn’s touchstones, Inglorious Basterds, so handily illustrated, there are few characters more despicable than a jovial, carefree Nazi.

So good is the interplay between Bacon and Fassbender, Fassbender and McAvoy, that it’s almost a shame when other characters intrude, which they do unwelcome and often with only the thinnest layer of characterization, particularly amongst the ladies. As Emma Frost January Jones is seemingly only permitted to act with her cleavage, while Jennifer Lawrence’s Raven/Mystique is reduced to a single-issue cipher whose only job it is to pout and slink about in skin-tight blue lycra.

Actually, the supporting boys fare no better. Only Nicholas Hoult, sporting an impeccable American accent, is worthy of our time as the conflicted and agonized Beast. Him aside, the good guy trio of Havoc, Banshee, and Darwin all suffer at the hands of some quite appalling special effects, while bad guy flunkies Azazel and Riptide are, for all intents and purposes, mute. Which makes you wonder just whose idea it was to include them anyhow?

Indeed, when First Class does creak it is under the weight of oh-so-many post-it notes from Fox executives determined to ensure the picture retains the kind of scattershot appeal that can so often ruin any superhero ensemble. ‘We need an effects-heavy sequence here. We need a broadly comedic training montage there. We need more shots of the female characters in various states of undress, well, everywhere!’ All unwelcome asides that only serve to overcrowd what is a fast-propelled but bloated picture, and undermine a far more interesting central dynamic that is otherwise as strong as Adamantium.

Starring: James McAvoy, Michael Fassbender, Kevin Bacon, Jennifer Lawrence, January Jones, Rose Byrne, Nicholas Hoult

Director: Matthew Vaughn

Runtime: 132 Minutes

Distributor: 20th Century Fox

Rating: PG-13