Green Belt activists are stepping up their campaign against a company which is selling plots of protected Green Belt land near Borehamwood.

UK Land Investments, a London-based company, has already sold more than £1 million-worth of undeveloped land off Theobald Street between Radlett and Borehamwood.

Although planning officers from Hertsmere Borough Council consider it highly unlikely' that planning permission will ever be granted, the company has sold more than 100 plots of approximately 200 sq m to would-be investors.

The Elstree and Borehamwood Green Belt Society this week sent letters to councillors urging them to oppose the scheme.

Chris Lewcock, a council planning officer, said: "The site is in the Green Belt and enjoys a considerable level of protection. The site is also part of a wildlife site and forms part of the green buffer between Borehamwood and Radlett.

"At the moment, and at least until the current local planning agreement ends in 2011, there is no chance of planning permission being granted.

"After 2011, in my opinion it will still be important enough to be a part of the Green Belt."

Although UK Land investments emphasise that the land is sold without planning permission, its sales brochure says: "Development of the site will be resisted initially by the local authority, Hertsmere Borough Council, due to its Green Belt allocation. Professional and proactive promotion will therefore be undertaken on behalf of all individual owners, setting out the case for a review of Green Belt boundaries and a change in policies relating to the development of the land."

Derek Laurence, of UK Land Investments, said that given the increasing pressure for housing, particularly in the south-east, the council will eventually have to look beyond its urban confines to fulfil its housing need.

"In terms of location it would represent the logical extension of the urban area as it is now," he said.

Ann Goddard, of the Elstree and Borehamwood Green Belt Society, said: "Once the Green Belt is lost it is gone forever. Our town is so close to the London surburban sprawl and has seen considerable overdevelopment and borne the brunt of new building.

"We support the council in its opposition to the Theobald Street development and have begun a campaign with the local residents' protest group to draw attention to it and our MP James Clappison is in full agreement with us."

Plots of land on the site have been advertised for sale for between £12,500 and £17,500.

The site was previously owned by the United Synagogue, which wanted to use the land for a burial ground but were unable to gain planning consent.

The previous owners would be entitled to 50 per cent any profits made on the land should planning permission be granted.