Few animals are more terrifying than the plesiosaur, a marine reptile that lived in British waters between 215 and 66 million years ago. Archaeology studies suggest these beasts could have been up to 49 feet (15m) long and weighed 45 tonnes.

At the end of its snake-like neck and head, its mouth was filled with razor-sharp teeth used to feed on fish. The first two complete plesiosaur skeletons were discovered by a pioneering female palaeontologist called Mary Anning in Lyme Regis in 1823.

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28 extraordinary animals that once lived in the UK