★★★★☆

MEL Gibson steps behind the camera for the first time since 2006’s brutal Mayan action adventure Apocalypto for this similarly uncompromising gut shot of a WWII film.

This isn’t an ordinary war film about brave men joining to fight for their country, bearing arms to do so. No, this is the tale of Desmond Moss (Andrew Garfield), an idealistic young man who wants to serve without firing a single bullet.

Despite pleadings from his battle-scarred WWI veteran father Tom (Hugo Weaving) and distraught bride-to-be Dorothy (Teresa Palmer), he signs up and goes off to fight as a conscientious objector.

However, his obdurate refusal to even touch a gun, much less take another human being’s life, causes troubles during his training – “You know, quite a bit of killing does occur in a war,” he is blankly told by his miffed Captain (Sam Worthington) – and he is even threatened with a military prison. But refusing to back down from his principals, he is eventually allowed to serve as a pacifist medic among the madness.

It’s an unashamedly idealistic film through and through. The earlier scenes almost feeling cosy (sometimes to a fault) as Desmond courts his future fiancé and speaks with pride about how, “while everybody is taking life I’m going to be saving it, and that’s going to be my way to serve”.

This is to reflect the principled path Desmond has set for himself: from the beginning right up until its credits – which inevitably show the real life man himself - the film holds him up as a special kind of war hero.

The Hacksaw Ridge of the title is the so nicknamed main battleground during the Battle of Okinawa and the centre-piece of Gibson’s unrelentingly brazen approach to wartime action. Although violence within his directorial work is certainly not a new thing – lest we forget how brutal and bloody the likes of Braveheart and The Passion of the Christ are – it nevertheless feels like a fresh and reinvigorated directorial style. The initial assault as the men climb up and over the ridge on a massed web of rope is a masterclass in horribly, unflinchingly realistic carnage: bullets whizzing and thudding against and through bodies as they run and shoot and fall and blow up, engulfing the frame to give a realistic sense of what it would have been like. It’s one of the best war movie sequences since the opening of Saving Private Ryan, one that contains some truly stark imagery that stays with you.

The film presents an interesting dichotomy between Desmond’s wide-eyed, almost romantic view of what war will be like for him and the horrors of what it’s actually like once he’s up on the ridge, scrambling with his medical kit among the bloodshed.

Is it arrogant for him to think he can serve without firing a gun while other men gladly put their lives on the line at the barrel of one? And what happens when he’s posed an immediate him-or-me threat on the battlefield?

Set to an at once rousing and pounding score by Rupert Gregson-Williams and anchored by Garfield’s committed and powerfully moving performance, this is Gibson back after a decade to show that he can direct the hell out of any story. The fact that it’s such an incredible true one makes it all the more effective.