Don Siegel's 1956 The Invasion of the Body Snatchers was the first movie based on Jack Finney's novel of the same name. Since then, several films have explored the idea of alien possession of the human body - it's a potentially rich theme, full of disturbing possibilities and psychological and political undercurrents, and some are discussed in a DVD extra. But this latest version is a confused jumble of action, suspense and speculation, punctuated by moments when it appears to be heading in an interesting direction. Nicole Kidman plays a psychiatrist who works out with remarkable speed what's going on: why it is that people around her have become strangely compliant yet threatening, why it's imperative not to fall asleep, and why projectile vomiting is an even more unpleasant phenomenon when aliens are involved. But the film feels incoherent and overblown, its menace dissipated by action. Part of the problem with The Invasion is undoubtedly a result of its chequered production history. German filmmaker Oliver Hirschbiegel ( Downfall) has the sole director's credit but there were, apparently, re-shoots and additional action sequences, presided over by the Wachowski brothers.