Leaky dams may not sound ideal but they are being used to great effect on dried-out marshland in the English West Country to produce fresh habitat for carnivorous plants and a spider that whizzes over the surface of water to grab prey.

Bales made out of heather and bunds constructed out of peaty soil and timber are being used to create porous dams on two mires, Agglestone and Greenlands, in Purbeck, Dorset.

The idea is that they block artificial ditches originally dug to drain marshes for conifer plantations or to graze farm animals and encourage the water to seep away slowly and “rewet” the dried-out mires, which are managed by the National Trust.