A campaign against a proposed supermarket development in the West Country is harnessing the support of a local celebrity.

Grand Designs presenter Kevin McCloud has joined the fight against a large supermarket on a derelict site in Frome, near Bath. Property developer St James Investments has announced plans for a supermarket with a footprint of 40,000sq ft, plus a further 40,000sq ft of retail space and 500 car parking spaces.

McCloud said the development should be in the hands of local people. “We will not create distinctive local towns that thrive economically and are a pleasure to live in if we make them all identikit places devoid of local businesses,” he said.

“In the spirit of local enterprise we should all be fighting off the big national retailers, and be supporting the council, writing to our MP and reminding those in power that big commercial proposals for small towns run counter to the government’s agenda for localism and the Big Society.”

Luke Wilde, chairman of the campaign group set up to oppose the supermarket plans, said McCloud’s support marked a “critical point in our campaign”.