If you’re ever having a bad day – say, the milk’s gone off, or your phone battery’s died – spare a thought for the trio of poor backpackers in The Human Centipede. Captured by a raving loon of a German surgeon, they become key players in his whacked-out experiment – forming the segments of, yes, a human fucking centipede.

A crazy concept that near trumps even David Cronenberg in the body horror stakes, Human Centipede is all about taking a gross notion and executing it in the grossest, most visual way possible. It’s telling that the film’s far more effective in its slowburn first half, when simply the idea of what is going to happen to our innocent victims is enough to get the stomach churning.

When the operation’s over, however, Centipede loses its legs. With the full horror of the idea fulfilled, all that can possibly follow is a string of scenes that hammer the point home. Repeatedly. Until the film caps things off with a tacked-on bloodbath finale and sudden ramblings about God and what it means to be a human being.

It’s a shame, because Centipede clearly has lofty aspirations, even if it is a glorified B-movie. Cronenberg’s already been mentioned as an obvious inspiration, but director/writer Tom Six hasn’t quite got the script to back up such spirited ambitions. The dialogue is often cruddily repetitive (I lost count of how many times the two girls screamed each others’ names, and that’s only in the first 10 minutes), while characters repeatedly do stupid things that means they very nearly deserve what happens to them. Nearly.

On the plus side, Dieter Laser at least gives a commendably creepy performance as Dr Heiter – one scene in which he sobs at the unveiling of his masterpiece (while the masterpiece itself howls in agony) is particularly effective. On the other hand, another scene in which he screams “Feed her!” as number one in the centipede line-up attempts to not do a number two is ridiculous to the point of absolute farce.

For Six, Centipede seems to be an attempt at updating the Frankenstein mould for the 21st century, mixing in a little traveller’s warning and freaky-deaky ‘this could really happen’ science for good measure. While he’s not entirely successful in his delivery, Six should, I suppose, at least be congratulated for coming up with such a sickening premise. And this is only the ‘First Sequence’. God knows what Six has dreamed up for the in-production ‘Full Sequence’, but on the evidence of this bloody (and bloody silly) first go, it’s hard to tell who’ll bother tuning in a second time. 2/5