Ecologists are celebrating after discovering a mammal thought to have become extinct in central Sussex.

The Environment Agency (EA) has found a small population of water voles in the Lancing Brooks and has called on the area to be protected by local authorities.

Mark Elliott, Sussex area ecologist for the EA, said: "We had begun to think the water vole in Sussex was about to become a thing of the past.

"The protection of the voles in the Lancing Brooks is now of paramount importance".

Immortalised as Ratty in Kenneth Grahame's Wind In The Willows, the once common species has suffered a catastrophic decline.

Between 1989 and 1996 numbers reduced by nearly 90 per cent, from more than seven million to fewer than 900,000.

Water voles, described by Grahame as having "a grave brown face with whiskers, small neat ears and thick silky hair", are not protected in law and have long been treated as vermin.

The killing of water voles by mink and the loss of wetland habitats alongside rivers through development and intensive farming contributed to their decline.

An EA survey of Sussex has revealed the species was extinct in the Arun, Adur and Ouse valleys.

Peter Midgley, Sussex area manager for the EA, said: "The Lancing Brooks is one of the last vestiges of coastal plain habitat left in Sussex.

"It is imperative we work with the adjacent local authorities, residents and conservation groups to ensure this unique green space is wholly protected."