While she will forever be known as a thriller writer, PD James' career also found her staring into the futuristic abyss with 'The Children of Men', her 1992 award-winning book which has now been turned into one of the best films of 2006.

Set in 2027, 'Children of Men' presents us with a world where no baby has been born for 18 years. Britain has become a rundown totalitarian state where armed guards monitor every street, illegal immigrants are deemed the greatest danger to national safety, religious fundamentalism is rampant and suicide products are advertised on television. Waging a campaign to overthrow the powers that be amidst this chaos are The Fishes, an armed group that counts Julian (Moore) among its leaders.

Moore's former lover Theo (Owen), a one-time political activist himself, has given up - passing his days as an office drone and drinking heavily. He's roused out of his slumber, however, when Julian gets in contact, offering him money if he'll help her with a secret that could change the world - and him.

Mexican director Alfonso Cuarón's career has been nothing if not varied. He's jumped from 'Great Expectations' to 'Y Tu Mamá También' to 'Harry Potter' and now this, his best film to date and one which warrants repeated viewing and plenty of soul-searching. It's too good and important a film to reveal too much of the plot; it does have some holes, but the feeling you get watching it is a mix of exhilaration and terror.

Combining thriller conventions with social and political commentary, Cuarón doesn't hold back in his depiction of a Britain falling over the brink, but what makes the film so compelling is that the viewer can trace a line from events today to what they're seeing on screen. The vision of a not-too-distant future presented here is brilliantly realised - so much so that it compensates for the areas of the storyline that needed further development and explanation.

Cuarón and his cast also deserve a lot of credit for making sure that all the performances are suitably underplayed so as not to take attention away from the bigger issues. Owen is excellent as the everyman who rediscovers a meaning to his life, with a little of the gloom lifted by Caine as his stoner pal and Mullan as an unhinged immigration guard.

And while the ending is too spectacular for the mood which preceded it, you won't see anything else that will scare you as much this year.

Except for the news, of course.

Harry Guerin