YOU KNOW a film is in trouble when, halfway through, the characters sit down and offer each other (and, therefore, us) a helpful summary of the impenetrable plot.

Sometime after a predictably gruff Vin Diesel reaches New York of the future - basically Blade Runner'sLA with poorer effects - High Priestess Charlotte Rampling gathers her cronies round a table and talks them through a heap of gibberish so nonsensical it could form the basis for a real religion.

I won't attempt any serious précis, but, suffice to say, Rampling, inhabiting a queasily similar character to the one she played in John Boorman's barmy Zardoz, seeks a particular young woman who carries within her the genetic potential to produce a messiah.

I think I have that right and, if I don't, who cares? It's not as if you had any intention of going to see a Franco-American co-production starring Diesel as a post-apocalyptic mercenary. Now, did you?

To be fair, the first 20 minutes of Mathieu Kassovitz's film are quite promising. Arriving in a future that combines equal parts crummier Children of Menwith cheesier Mad Max II, we find Vin being abducted by Gérard Depardieu, an evil mastermind, and handed an awesome task. He is to transport the mysterious young girl (vapid Mélanie Thierry) and her teacher (good old Michelle Yeoh) from Mongolia to New York, via the ice-bound Baring Strait and Canada. Some entertaining chase action follows before the ludicrous, teetering superstructure of the conspiracy plot looms over the horizon and overpowers any hope of reason.

This version of the film is some 11 minutes shorter than that released in France, but it makes so little sense you feel a further half hour must have gone missing even before it arrived in Paris. None of which is to suggest we would prefer it any longer.