Shark, BBC One

It is perhaps a clever piece of ironic perversity to have scheduled the first part of a three-part documentary on sharks on polling day, but the subject here is the comings and goings inside the complex world of the predators of the sea. The series is an amazing feat on the part of the BBC Natural History Unit, in tandem with the Discovery Channel.

The images from under the ice in the Arctic to the South African ocean and the Great Barrier Reef are in themselves awesomely beautiful and mysterious, as we investigate the natural world in ways that were never possible before the revolutionary advances in cameras and other equipment. It is also the 40th anniversary of Jaws, the film that encouraged an uninformed worldwide horror of sharks. And now sharks everywhere are threatened, even though their survival record hitherto has been impeccable. Several species are almost literally living fossils, their biology unchanged from 400 to 100 million years ago.

There are 510 different species of sharks and rays, the programme examining a mere 30 or so from all over the world. The smallest shark could fit into the palm of our hand; the largest is over 40 foot long; and the fastest, the Mako shark which hunts tuna in the open ocean, can travel at over 40mph, as attested by a motorboat trailing a speedometer. Dolphins can manage a mere 20mph. The epaulette shark can walk on land as it traverses from tidal pool to tidal pool on the Great Barrier Reef, while the six-foot-long blacktip sharks band together to feast off 10-million-strong anchovy shoals traversing the South African oceans.

From a coral reef in Melanesia, there was astonishing film of the Tasselled Wobbegong shark (pictured above) which is camouflaged to look like coral, lying in ambush to snatch dinner. The reefs also harbour whitetip sharks who hunt in the dark in a mob, detecting their prey by sensing the electrical charges given off  by the frightened heart of the victim. Half a mile under the Arctic ice there are Greenland sharks, blinded by little white parasites attached to and eating their eyes. These scavenger can live for up to 200 years, at pressures 100 times greater than those on land.

The climax was the Great White shark (pictured above with nervous cameraman) chasing the fur seals feeding in the open ocean off Cape Storm, South Africa. We witnessed the incredible sight of a huge one-ton shark, travelling at 20mph, leaping out of the sea to bring down a seal in mid-air. All that remained was the victim's blood pooling across the ocean’s surface.

The amount of information imparted was  prodigious, though as ever the BBC couldn't leave well enough alone. Composer Will Slater was doubtless working to a brief, but the background music was melodramatic, overwrought and often completely unnecessary, while the voice-over was studded with clichés about “the world beneath the waves ruled by strange fearsome creatures”. Nonetheless, there's plenty more to look forward in the two remaining films, which promise to explore shark society, from networks of communication to family life.