WORKING ON THIS PHOTO-STORY BENEATH ARCTIC ICE in Greenland was a logistical nightmare. The ice, about 2m thick, lay over a frigid sea more than 300m deep. Water temperature was zero. But during the night, our Inuit guides managed to attract a sleeper shark (Somniosus microcephalus). They also cut holes into the ice to allow me to dive with it.

Only eight shark species have been reported in Arctic waters, and one of these is the sleeper, otherwise known as the Greenland shark.

It passes the time at around 550m in summer, moving into shallower waters only in winter.

I admit to have had some doubts about diving with a shark capable of growing to more than 6m in length and weighing almost 1 ton. The Greenland shark is regarded as a slow-moving deepwater scavenger, yet fast-moving prey such as salmon and seals have been found in its stomach.

The shark is believed to use its striking glowing eyes to lure its prey within striking distance - the glow comes from bioluminescent parasites.

I had many factors to consider now: light, water clarity, lens, flash and film. I decided on a fast film, 200ASA, to get some natural light into the frame, and a fisheye lens to suit the size of subject and the particles in the water.

I attached two flashes with long arms so that I could angle them and have them far behind the camera.

I went in roped to the surface for safety. I could see the hole in the ice from below, and chose to shoot the sleeper shark against this background.