Two years from now, every woman on Earth becomes infertile. Another eighteen years later, the world has descended into near-anarchy. In the United Kingdom in particular, illegal (that is to say ALL) immigrants are being rounded up into refugee camps, terrorist attacks are routine, and you need your papers at every checkpoint. The world is black and grey and the streets are filthy. Suicide pills come with your food rations.

Clive Owen, disillusioned activist-turned-bureacrat, is dredged up by his activist-turned-radical ex-wife Julianne Moore to help transport the mysterious Claire-Hope Ashitey to the south coast. Turns out she's the most important person on the planet. Turns out she's pregnant. Michael Caine plays a buddy of Owen's; Chiwetel Ejiofor (of Serenity fame) plays an ally of Moore's. Alfonso Cuarón directs; P.D. James wrote the original novel, "The Children Of Men", on which this is based.

This isn't a science fiction movie. In fact it doesn't seem much like fiction at all. The world presented here is (almost) absolutely believable. Explosions billow grey smoke, not red fire like in Hollywood. Gunshots are as terrifyingly loud as they are in reality. It doesn't even seem like there would have to be a sudden absence of children for it to happen. The real lesson I took away from it is: THIS is what happens if everything continues as it has done for the past five years. This is what the world is like, twenty years further down this road.

Let me see here, positive points:

• All the acting is stunning. Seriously. Everybody behaves like a real person under real circumstances with real motivations. Because of this, you are sucked RIGHT in. A lot of this movie resonates very strongly with the opening sections of the videogame Half-Life 2 - if you've played that game, then you'll know how amazing it is, so you will find it even more amazing when I tell you that this movie is more immersive, more moving. Which is not what you'd think from a non-interactive medium.
• All the emotions the movie wants you to feel? You will feel them. Sadness, fear, horror, unbelievable tension.
• The effects are unbelievable. Even in this age of cheap, universal, highly believable CGI, there are at least three shots in this movie where I really have absolutely no idea how they were filmed. That, in this day and age, is a VERY impressive achievement.
• Hell, do you really need more than that?

Negatives?

• You know that thing movies sometimes do where everything seems to be tinted in a single colour, just to emphasise the emotions attached with that colour? Children Of Men is a washed out grey, start to finish. Admittedly World Trade Center (trailered before it) is even an even worse offender - pre-crash clips are soppy, glowy, soft-focus orange and post-crash clips are harsh and grey - but I could have stood a little more colour.
• Not many laughs. This isn't a fun movie. It's stone-edged and compelling human drama. Think Schindler's List.
• I found the ending to be a little unsatisfactory. I really can't say much more without spoiling it, though.

Best movie I've seen since The Incredibles. A+.