Like “Avatar”, perhaps the most blatant thematic point of the first 20 minutes seems to be that you really just shouldn’t mess with nature. But as the film launches, there’s a bit of Cameron-esque idealism that comes through almost before the showy visuals become noticeable. The obvious starting point is, of course, the use of 3D. But it's pretty, has a couple of cool death scenes (the 'hair' moment is horrible) and it's much, much shorter than The Abyss.Playing “spot the Cameron” is a fun way to pass the time during a screening of this perhaps otherwise uninteresting undersea spelunk. Yes, the cave is surprisingly well-lit and yes, saying 'what could possibly go wrong' before abseiling into the bowels of the earth is utterly stupid. From the ethereal splendour of a vast underwater cave to the pockets of air bubbling like mercury on the rocky ceiling, it's a feast for the eyes even when it leaves the brain starving. That said, there's some eerily beautiful moments of utter horror to be found. So when Grrr, Aaargh (Frank MacGuire), Whinging Son (Rhys Wakefield), Millionaire Jerk (Ioan Gruffudd), Comic Relief (Dan Wylie), Woman (Alice Parkinson) and Expendable Foreigner (Cramer Cain) find themselves trapped underground, you'll be more interested in how they're going to die than in the clunky dialogue. In fact, it's not that surprising that as his sticky fingers are all over the post-production and cinematography, this feels like a James Cameron flick where the script never got past the first draft. And you'll probably be able to figure out what order they'll run out of oxygen in as well.

Playing out like The Descent with more water and no monsters, it's a beautifully shot survival flick but it's populated with characters so bland that you won't care one bit if they survive or not. For a film that goes so deep underground, Sanctum is a remarkably shallow experience.

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