In reply to Blue Straggler:
I bust an £100 olympus point and shoot in Sell Gill Holes whilst caving, pissed wet through. Since then Ive used Fujica STX 1's bought off ebay at £20 a time, completely manual SLR, never let me down, lots of dings and scrapes but still working.
I had a Sea & Sea underwater camera dragged off my wrist whilst retreating very scared from the valve in Naden Reservoir, it went through several hundred yards of pipe, floated across the reservoir for a week and I picked it up on the far bank, pictures came out ok and then I sold the camera on ebay.