SET more than 20 years in the future, Children Of Men is a brilliantly orchestrated, nightmarish thriller adapted from the PD James novel about a world teetering on the brink of anarchy.

Mexican filmmaker Alfonso Cuaron (Y Tu Mama Tambien, Harry Potter And The Prisoner Of Azkaban), who co-wrote the screenplay with Timothy J Sexton, energises this fantasy with his directorial power.

He orchestrates a series of jaw-dropping action set-pieces that are staggering in their technical daring and breathtaking in their simplicity, seamlessly melding inventive camerawork with unobtrusive special effects.

It's a tour de force of edgy Steadicam shots that plunge the characters, and us, into the centre of a war zone, recalling the same visceral thrills on the frontline as Saving Private Ryan.

Buildings explode under heavy artillery bombardment, background characters are scythed down in a hail of bullets and all hope is lost amid the bloodshed.

The year is 2027. Women are no longer able to conceive and the human race is dying out.

Half the population is grimly resigned to its fate and determined to toast the end of mankind; the other half struggles to maintain law and order, despite dwindling resources and little hope of finding a cure to the pregnancy crisis.

One-time activist turned government bureaucrat Theo (Clive Owen) has given up caring, too badly scarred by the separation from his partner Julian (Julianne Moore), and the death of his young son.

During a walk through the cluttered streets of London, Theo is kidnapped and finds himself face to face with Julian and her comrades from a rebel outfit called Fish, which fights for the rights of Britain's vast refugee population.

Julian needs an urgent favour - transit papers for a fugee' called Kee (Clare-Hope Ashitey), who must be granted safe passage through the various checkpoints to the coast, where she will be taken into the protection of the mythical Human Project.

Theo reluctantly agrees but a bureaucratic glitch means he is forced to accompany Kee on her hazardous journey.

En route, he learns the young woman's shocking secret.

"She's pregnant!" gasps Theo.

"I know," replies Fish activist Luke (Chiwetel Ejiofor), "Now you know what's at stake."

Owen delivers one of his best performances as a lifeless man, whose activist spirit is unexpectedly reignited by his contact with Kee.

He's in almost every single shot of the film and effortlessly holds our attention, generating a touching screen chemistry with Ashitey.

Moore impresses in her pivotal supporting role, as does Michael Caine as the ageing hippie and political cartoonist who sells cannabis and still believes in a world of free expression and beauty. Such a beautiful dream.

Swearing, no sex, violence Rating: Five stars