Typically tropical? This kaleidoscope of sealife lives near you

The astonishing colours – brilliant reds and pinks, vivid emerald greens and sapphire blues, luminous yellows and oranges – are what you would expect to find on the reefs of a tropical ocean.

But this is not the tropics, this is the cold sea around the coast of Britain. In his new book, Great British Marine Animals, Paul Naylor reveals the remarkable specimens living just off our shores and displays them in their full colourful glory.

The North Atlantic dull? Never. From the snakelocks anemone to the lightbulb sea-squirt, from the candy stripe flatworm to the tompot blenny fish, Dr Naylor's photographs disclose a world that is intensely colourful not only in the visual sense, but also because of the behaviour of its varied inhabitants.

Britain has more than 7,000 species of creatures in the seas around its coasts. Dr Naylor, who published the book privately with the help of a friend, has pictured more than 200 of the most common ones.

The photographs show the bootlace worm, which can grow to more than 100ft in length, making it Britain's longest animal. The wolf-fish, which grows new teeth every year, sea-slugs, which form mating chains, and curled octopuses, which inject poison into crabs to turn their insides into soup, can all be seen in the book.

As a trained marine biologist, he is a regular diver and underwater photographer during time off from his full-time work as an environmental safety consultant. The 351 colour plates in the book represent about 10 years' diving all round the British Isles, and can be used as an identification guide for non-specialists.

Dr Naylor's passion for underwater life began during his holidays to Norfolk as a teenager. He discovered the sub-aqua world by snorkelling in less than a metre of water. Since then he has dived all over the world, from the Red Sea to the Great Barrier Reef, but never lost interest in his home waters.

He writes in the introduction: "Too many people seem to think our seas are grey and uninteresting, a view which can only reinforce an attitude of indifference to what we put into and take out of them. All the world's oceans and their inhabitants are under pressure from a variety of environmental threats. The cool northern rim of the Atlantic needs our care and attention in just the same way as does the warm splendour of coral seas."

Other species shown in the book include the sea mouse (a type of worm), the sea hare (a type of slug), and the sea cucumber (a relation of the starfish). The sea beard, the sea pens and the sea fans (all hydroids or coral relatives) colour its pages. While the football jersey worm plays, as it were, in brown-and-white stripes.

"Great British Marine Animals", by Paul Naylor, £14. Available from bookshops, dive shops or through NHBS mail order bookstore, 01803 865913, www.nhbs.com