LAKE District planners say a modern extension to a unique and historic folly in the grounds of Duddon Hall, near Broughton-in-Furness, will look like a "skip" or a "shipping container".

But despite some members' concerns that the bold steel and glass design would spoil the folly, the national park authority's development control committee has agreed to grant permission for it to be converted and extended to create a house.

Built in 1843 in the style of a Greek temple, the folly is a Grade II Listed Building. But it is now out of use and badly in need of expensive renovation work. The applicant A.W. Bowness says the conversion scheme will include measures to secure the fabric of the building and would ensure its future upkeep.

But commenting on a computer-generated photo-montage of how the extension would appear, county councillor Alan Clark said it looked like a "skip".

"I really do feel we're being blackmailed to approve a dreadful building to save a magnificent building," he said. "This is a skip they've put next to the folly. I would recommend we renegotiate for a better design."

County councillor Ronnie Calvin said the extension looked like a "shipping container" and did not blend into the landscape.

The Ancient Monument Society also opposed the scheme and there were six letters of objection from local people.

However, the authority's buildings conservation officer Andy Lowe supported the scheme and said it would not compromise the "strong character" of the folly.

"I believe that this is a rare opportunity to demonstrate that confident modern design can sit comfortably with a unique historic building and help to secure its long-term future," he said.

After a proposal to defer the application for renegotiation was defeated by the chairman's casting vote, the committee approved the scheme by eight votes to six.