'The Body Snatchers' remake: they're coming to get you...

It is unlikely that Jack Finney imagined his novel about aliens taking over the citizens of a small American town spawning a handful of film adaptations. Fifty-three years after its serialisation in Collier's magazine, however, a fourth version of The Body Snatchers, titled The Invasion and starring Nicole Kidman and Daniel Craig, is about to land in UK cinemas.

Did we need another one? The film's producer, Joel Silver, certainly thinks so. "In an era of enormous political, social and environmental paranoia, it really felt that now was the right time to make this film," he says.

Silver has a point. Previous body snatchers films have all, to a greater or lesser degree, tapped into the anxieties of the eras in which they were made. In the post September 11 landscape, Finney's chilling concept is unquestionably worth revisiting.

The Invasion has at least two hard acts to follow, though. Don Siegel's 1956 version, Invasion of the Body Snatchers, is generally regarded as a classic, and, of the four films, cleaves closest to the original story.

In it, Dr Miles Bennell (Kevin McCarthy) returns to the friendly Rockwellian town of Santa Mira to find that its inhabitants are changing. People look and sound the same, but they are hollow, affectless shadows of their former selves. Gradually, Bennell discovers that alien vegetable pods are replicating humans as they sleep, replacing them with emotionless doppelgangers.

Siegel's iconic final scene – softened with an epilogue by the studio – has Bennell running among traffic, crazed and desperate, screaming warnings to drivers about the danger that is spreading across the country. Looking directly down the camera lens at us, he cries: "They're already here! You're next! You're next!"

This was the age of the Red Scare, and Invasion of the Body Snatchers practically quivers with Cold War fears. But the film's enduring power stems from its ambiguity. Are the aliens turning Uncle Sam's citizens into cold-blooded conformist Commies, or was the film's screenwriter, Daniel Mainwaring, who was a victim of the Hollywood blacklist, actually talking about the deadening impact of McCarthyism, and the paranoia that had gripped the film-making community? As Philip Kaufman, director of the acclaimed 1978 Invasion of the Body Snatchers, noted, the film can be read as either "anti-Communist" or "anti-anti-Communist". "Both theories seem to make sense," he said.

Siegel always denied that his film had a political message, although he acknowledged that it reflected a phenomenon he recognised. "I think the world is populated by pods and I wanted to show them," he said. "Many of my associates are certainly pods. They have no feelings. They exist, breathe, sleep. To be a pod means that you have no passion, no anger, the spark has left you... People are becoming vegetables. I don't know what the answer is except an awareness of it. That's what makes Invasion of the Body Snatchers important."

Kaufman felt much the same way when he took on the risky job of updating the story. Like Silver now, he thought the late 1970s was "a perfect time" to restate the message of The Body Snatchers. "We were all asleep in a lot of ways in the Fifties," the director said at the time, "living conforming, other-directed types of lives. Maybe we woke up a little in the Sixties, but now we've gone back to sleep again. We've taken some of the things that were expressed about the original film – that modern life is turning people into unfeeling, conforming pods – and we're putting them directly into the script."

Shot through with a sly wit, Kaufman's film relocates the action to the world's counterculture capital, San Francisco, to comment on the drift away from the free-thinking 1960s towards a more conservative society. Flowers that were once the symbol of the peace and love generation are now harbingers of a loveless conformity, presciently foreshadowing the Reaganite "me" decade. The film is steeped in post-Watergate paranoia and displays a healthy mistrust for the psychobabble of self-help gurus. Cultism has become the danger.

And now it's the turn of The Invasion. Throughout the body snatchers films, the aliens promise a world free from anxiety and hatred. Provocatively, The Invasion almost makes giving up one's humanity appear a good idea by touching on current crises and imagining what might happen if the world were not comprised of individuals but of a species that thought of itself as a single entity. As people are transformed globally by a virus from outer space, the Americans withdraw from Iraq, Presidents George Bush and Hugo Chavez become allies, the dispossessed of Darfur are fed, and Kim Jong Il signs up to a unilateral nuclear disarmament treaty.

Meanwhile, as the representative of humanity, Nicole Kidman's character discovers the truth of the claim that "in the right situation, we're all capable of the most terrible crimes" as she fights for the life of her son. He is immune to the virus, and symbolises humankind's best hope of survival.

Expensive and starry, The Invasion is not entirely successful, showing obvious signs of the rumoured re-writes and re-shoots that were done after the film's distributor, Warner Bros, was reportedly unhappy with the lack of action in the German director Oliver (Downfall) Hirschbiegel's original cut. Nonetheless, it remains a compelling and provocative film that proves there is still plenty of life left in Finney's brilliant concept.

Indeed, in an age when pod people seem to be everywhere – in the media, in government, in the body politic – it surely can only be a matter of time before the next invasion.

'The Invasion' opens on Friday