Frozen Planet II

BBC1, 8.05pm

The brilliant series presented by Sir David Attenborough continues with a fascinating look at the expanse of the Arctic Ocean. Even bigger in area than the United Stares, this is a natural kingdom in which the indigenous species must adapt to brutal conditions that shift from steel-hard ice to water as the seasons change.

Brace yourself for snow that has been streaked crimson with blood after polar bears feast on seal pups (right), while bowhead whales come under repeated violent attack from killer whales careering into them at speed so that they can prey on their remains. Even the charming displays of crested auklet seabirds to entice a breeding partner leave them vulnerable to the unwanted attentions of the Arctic fox.

But there is some light relief too, in the blubbery walruses who waddle with comical slothfulness on dry land. ★★★★★