The lichens growing on the post indicate the high air quality and lack of pollution on Exmoor.

An old wooden signpost from a national park is on display in the Natural History Museum, due to having 12 species of lichen living on it.

The fingerpost from Exmoor has been part of the ‘Fixing Our Broken Planet’ exhibition at the museum since April to act as an example of an item recovered from an area with clean air.

Organisers said the aim was to help educate people and “explore nature-based solutions that can help create a more sustainable world”.

Ranger Charlotte Wray, who assisted in the recovery of the post, said it was “such a joy to help tell the story of Exmoor”.