One of the country's top widlife sites is under threat from litter thrown from cars.

A viaduct carrys the A20 over Holywell Fen, a piece of land between Sugarloaf Hill and Castle Hill, outside Folkestone.

Due to its history as a bog, it has well-preserved examples of flora and fauna going back to the last Ice Age in Britain and is a Site of Special Scientific Interest as well as containing evidence of ancient civilisations, before the Romans.

But litter thrown from vehicles using the viaduct is threatening the site.

Volunteers from the White Cliffs Countryside Project filled more than 20 sacks in a few days.

Phil Green, of the WCCP, said: "My opinion is they should never have built the road as it is one of Britain's top wildlife sites.

"The Holywell Fen is a wetland site that has never been built on or farmed.

"They have pollen samples going back to the last Ice Age."

The area is also rich in orchids and butterflies.