A conservation group is opposing an electricity company's attempt to install new overhead power lines.

EDF Energy Networks wants to renew lines and cables between Lewes and Newhaven in the Ouse Valley.

But the South Downs Campaign said the equipment was a "major blight on the landscape" and should be placed underground.

The Ouse Valley is part of the Sussex Downs area of outstanding natural beauty and will become part of the South Downs National Park when the designation is made.

The South Downs Campaign said it was concerned people had not had enough time to object to the lines.

Chairman Robin Crane said: "This is a once-in-a-lifetime opportunity to remove this scar on the landscape.

"The original power lines should never have been built and we doubt whether they would be allowed today.

"We want to see every effort made for their removal. It might be more expensive than just simply replacing the overhead wires but it would be a small price to pay to restore the landscape to its previous splendour.

"The South Downs is one of the most heavily-visited landscapes in Britain and supports some 8,000 jobs, bringing in more than £333 million to the regional economy annually.

"It is vitally important for economic and social as well as environmental reasons."

EDF Energy Networks said it was investing £346,000 to replace about 8km of 132,000 volt overhead power lines as part of vital maintenance work.

The project will improve the reliability of power supplies.

Although EDF Energy Networks is working to remove lines from some landscapes in the South-East, putting these particular lines underground would cost £8 million and would be difficult because of geographical constraints such as rivers.

The firm said it had contacted English Heritage and other environmental groups before submitting its plans to East Sussex County Council and Lewes District Council.

A public notice was issued on May 2 to allow people a full month to respond longer than the statutory minimum of 21 days.

The Department of Trade and Industry will make the final decision.

A spokeswoman for the power firm said: "EDF Energy Networks is committed to the environment and is one of the first companies to set up a scheme to work alongside agencies that look after areas of outstanding natural beauty."

She said it was already working with the South Downs Joint Committee on other projects for putting overhead lines in the South-East underground.

Some schemes have been given the go-ahead, including a project to remove about a mile of overhead lines in the Adur Valley in Upper Beeding in the Sussex Downs area of outstanding natural beauty.