Sanctum review (3D Blu-ray) ★½

Oh dear.

No, you’ll want to read a longer review than that. OK, there’s this group of tunnelling and diving explorers in Papua New Guinea, led by Richard Roxburgh. He’s about as cardboard cut-out a character with as clunky dialogue as you’ll find. He has a friend, a fellow explorer and diver, female, who really shouldn’t go down and explore any more. He’s fallen out with his stroppy, teenage son.

So there’s a crisis in this tunnel where they’re diving in an underwater river and they’re visited by two old friends: a cavalier playboy type (Gruffud) and his new girlfriend, who by way of character depth is described as having climbed Everest. They can’t wait to get exploring too.

All of this is clear in the first few scenes. Equally clear is that the characters could have been chosen from any set of stock personas for a disaster movie, and that’s what we get. No twist, no character development, nothing unexpected. Clunk, clunk, thud, you can hear the story slotting into the predicted place right until the last few seconds when the surviving cast gets literally to the light at the end of the rather soggy tunnel (after, of course, the dad has gotten back together with his son and they’ve come to appreciate each other’s strengths). Did it really take two people to write this? I could have done it on the back of a fag packet if I smoked, and the dialogue’s just a list of clichés.

There are a couple of reasons not to detest this movie. First there are some genuine visceral thrills. One character drowns and Roxburgh tries to save her with “buddy breathing” – her reactions and the realisation she’s drowning is creepily convincing, she turns from professional to self-preserving, base angry savage in seconds. It’s disarming. There’s real power in the underwater river and you can feel it at times.

Better still – and yet more frustrating – is the exquisite 3D camerawork once you’re in the tunnel. Yes, the surroundings outside are decorative but it’s once we’re under water, exploring subterranean tunnels that we get a real idea of menace, of scale. It’s honestly one of the best uses of 3D I’ve seen and it adds serious depth to the picture, building up the menace nicely. I also liked the fact that the threats if not the characters were credible. Don’t waste time looking for sea monsters, aliens or other predators – there are none. Human curiosity and fallibility against nature are the enemies here.

All of which is why it could have been so good. The camerawork certainly deserves to be served by a better script – I can’t comment on the cast, they’re given nothing to work with.  As it stands this is a wasted opportunity – it’s a beautifully shot, good looking utter stinker.