'Only one species is getting out of this alive!' screams a character early in this post-apocalyptic yarn. Does he mean the flame throwing computer-generated dragons which raze the Houses of Parliament in London, England? Or Bale's plucky band of human survivors barricaded in a remote Northumberland fortress? It's a tough call. The script boils one spoon of DragonHeart fantasy spectacular with two big ladles of Mad Max action parody, with pinches of Fahrenheit 451 and other moral parables to taste. The director's general rule of thumb is to play it straight. But just as the film threatens to bog down in endless stuff about survival strategies and crop protection, the (American) cavalry arrives, headed by cigar-chewing battle tank driver McConaughey and his outrageous platoon of Kentucky 'irregulars'. The climactic SFX are well mounted and it's all too preposterous to dislike.