The group Cornwall for Change, representing 70 town and parish councils, said there was great concern about the way planning was being executed in the Duchy.

And their fight won support from the House of Lords late last week.

Campaigners said that Cornwall Council has already given permission for nearly 30,000 new homes, most of which are to be built on green fields around existing towns.

“This will increase traffic, have a big (bad) visual impact and make little or no benefit to locals who need genuinely affordable homes,” the organisers said.

“We need to make much smarter use of existing sites in and around Cornwall’s town centres so they can flourish once again.”

Orlando Kimber, spokesman for the umbrella group, said: “We are seeing 52,000 new homes planned, and all over the place they are being built on the green fields of Cornwall.

“Using brownfield sites would reduce the pressure on transport, and increase housing density in towns, which Cornwall Chamber of Commerce is in favour of.

“We recognise that Cornwall Council is under pressure with its budget, and we feel that whatever money it does have, it should spend wisely.”

He has previously called for an audit of brownfield sites in the Duchy, and gave the example of two suitable brownfield sites in Bodmin – the Walker Lines industrial estate and the MPG book factory, which is now acquired by Ocean Housing. …”