One of the best-known estuaries in Sussex could be turned into a vast wildlife refuge if plans to return it to nature come to fruition.

Man-made banks beside the channel, dug in 1846, would be taken away to allow the Cuckmere river to follow its natural course, flooding the valley.

Periodic flooding below Exceat would allow mud flats and salt marsh to develop, creating a vast wildlife refuge.

Wading birds in particular would return to the estuary once the river is diverted back to its famous meanders.

An artist's impression of how the valley might look was unveiled as the Environment Agency, the National Trust and English Nature launched the project yesterday.

Bob Edgar, of English Nature, said: "Natural estuaries along Britain's coastline attract huge numbers of migrating birds to spend their winters here.

"It is hoped the restored Cuckmere estuary will play its part in this network of sites in the future."

Allowing the valley to flood is expected to prevent flooding further upstream of Exceat - the west side of the valley alone is a huge reservoir capable of holding a million cubic metres of water.

At first, only the west banks of the 19th Century cut would be removed but barriers on the other side would go later.

The banks are nearing the end of their lives and would cost more than £1 million to replace.

The first phase of the project is hoped to start next autumn and an exhibition will be at the Seven Sisters country park visitor centre for the rest of the summer.

Mark Elliot, the Environment Agency's project manager, said: "We are delighted to invite people to view the artist's impression, meet some of the people involved and take away our new booklet outlining the project."

The National Trust, the main landowner, needs to alter the routes of some of the footpaths in the valley because of the changes.

Guided walks to explain the scheme will start from Seaford Head car park on Sunday from 3pm, Monday from noon and Tuesday and Wednesday from 6.30pm.