The name P D James usually guarantees a mystery story but this film, taken from her novel, strays into science fiction territory.

Director Alfonso Cuaron, of And Your Mother Too and Harry Potter And The Prisoner Of Azkaban fame, has turned it into an apolyptic vision of the near future - 2027 - where the world is in crisis.

Only Great Britain has managed to survive the internal strife, although faces being overwhelmed by a massive influx of illegal immigrants. Life is frequently interrupted by the terrorist-like activities of a group fighting for the rights of the remaining refugee population.

Using handheld cameras, long takes and a dark-and-dirty look, Cuaron conjures up a terrifying picture of a world at war with itself.

Enter Theo (Owen) as a hero in flip-flops, a former activist turned bureaucrat lured into helping the rebels by former lover Julian (Moore).

The mission is to help a young woman Kee (Ashitey) escape the country.

The reason soon becomes clear - she's pregnant, which is remarkable as society has been cut down by infertility.

There hasn't been a baby born for 18 years. The stabbing of the youngest person in the world at the start of the movie triggers a public grieving of Diana-like proportions.

Theo finds himself on the run with a pregnant woman, pursued by both military and rebels in a classic case of the reluctant hero pushed into action by circumstances outside his control as everyone determines to use the miracle baby for their own ends.

Owen makes a fine, thinking man's hero who finds inner courage to fight back and save Kee, leaving Caine to have fun as an ageing hippy and old chum of Theo who's living in the backwoods in a haze of pot.

What makes the movie work is Cuaron's fluid direction and handling of the action sequences, which include a car chase in reverse gear, an escape in a car that needs to be jump started and the final chaotic battle through a maze of crumbling buildings.

Steve Pratt