Probably the single most sustained assault of extreme and grisly violence unleashed on Planet Earth in its turbulent history, this extraordinary Japanese bloodbath is already causing serious kerfuffle among morally righteous observers, will probably be banned altogether from US screens, and should certainly pick up a negative plug or two in the Daily Mail. Racking one’s brains to think of any precursor that bears comparison leads you nowhere: the intensity and savagery of Reservoir Dogs might be a reasonable reference point, but Battle Royale truly is out there in a league of its own.

Making Fight Club resemble a particularly twee Robin Williams effort, the film dives right in at the deep end, accompanying forty-two teenage Japanese students on an excursion to some sub-basement of Hell. Battle Royale is set in a 21st-century, post-fascist Japan (if such thing could exist) where the imperial elders have long since tired of the nation’s moral decay, and the prevailing mood of indifference to human suffering is enough to confirm every paranoid WWII-derived suspicion of Japanese depravity ever held. Takeshi ‘Beat’ Kitano plays a schoolmaster named Kitano, a miserable and sadistic old bastard with obvious militarist/fascist leanings: the regime appears to have identified young people as the enemy, and deemed their lazy, insolent ways ripe for a short, sharp shock.

Thus, Kitano sends the randomly-selected kids onto a remote desert island for three days, all armed with weaponry of varying usefulness according to his whims, and instructed to kill one another off until only the one survives. The kids are far from thrilled, to put it mildly, but as soon as one of them dares to question Kitano he is done to death quite nastily with a knife in full view of all the kids. In no time, they’re all on the island waiting to kill or be killed.

Two hours of mind-searing bloodletting follow, several of the killings as sadistic and extreme as anything ever to pass a censor, and it’s recommended that even the very hardened viewer should be prepared to avert the eyes when necessary. If the relentless slaughter doesn’t put you off, though, you’re in for one of the most gripping, enthralling and thrillingly tense two-hour episodes in living memory, as the characters – real entities with vastly differing personlities, having already engaged our sympathies and hatreds – battle their desperate way towards an apocalyptic finale, the tension heightened by the certainty that only one will survive. In a rather sick, phenomenally enjoyable sense, it becomes almost sport-like to watch as the brutal Darwinian process of elimination works its way to a head.

Amoral, chilling, nihilistic, nasty and indefensible stuff, it might seem... and yet, this is by no means a heartless film or one totally devoid of humanity. Though no stone is left unturned in Battle Royale’s quest to out-gore anything witnessed outside Fred West’s home-made movie collection, it’s clear where most of the characters stand on the good-versus-evil spectrum, and it’s the more vulnerable and peaceful souls who assume the position of (what passes for) the film’s moral centre. Most memorable and engaging of all are a young couple named Tatsuya and Aki, too nice to kill anyone and too squeamish to even try, relying on the increasingly useless commodity of help-thy-neighbour goodwill to prolong their survival.

Nonetheless, Kitano commands all the attention every time he opens his mouth and often when he doesn’t: the psychopathic GAA instructor you’re glad you never had, this is probably his standout performance in a career laden with knockout ones.

While extreme caution is advised, Battle Royale is nonetheless an absolute masterpiece of magnificently executed ultraviolence in the finest Sam Peckinpah/Sam Raimi tradition, and easily the finest film to hit our screens all year, with the possible exception of drug-hell Hubert Selby adaptation Requiem For A Dream. If you’re sure you can handle it – and ‘it’ involves a constant bombardment of stabbings, throat-slashings, decapitations, and genital mutilations – you won’t regret it. If you can’t, go back to sleep.