Blue Planet II

In the undersea forests of kelp, algae and sea-grass, there is competition between species and sea otters are seen helping Garibaldi fish protect their seaweed garden from sea urchins while the common octopus uses shells to create a coat of armour against sharks.

The 620,000 kilometres of the world's diverse coastlines are a window to our oceans. After 60-mile journeys for food, puffins try to feed their young while dodging the attention of skuas.

The human impact on our oceans is brought to light in a sobering finale – like the eight million tonnes of plastic that ends up in the oceans every year.