Which is Britain's biggest slug?

Slimy, silent and surprisingly elusive, Britain's - in fact, the world's - biggest land slug is a creature of the night. The ash-black slug (Limax cinereoniger) is a remarkable nocturnal gastropod known not just for its impressive size but also for its climbing skills and secretive woodland lifestyle.

- Freya Parr

Despite its size, this species often goes unnoticed, hiding beneath logs and slithering up trees while the rest of the forest sleeps.

The ash-black slug typically measures between 10cm and 20cm in length, but some individuals have been known to reach up to 30cm. Adults are black or dark grey, whereas their juvenile counterparts are a warm toffee-brown hue.

A fully mature ash-black slug also has a white or yellowish ridge, called a keel, which stretches at least half of the length of its back. Its tentacles are spotted grey, and it has a pale stripe running along its foot.