Richard Webber in front of a Gothic Revival house in Broadlands Road Highgate which is featured on the circuit.

Basements being carved out of the earth below homes in Hampstead, Highgate and Muswell Hill have been the cause of great concern.

And some residents believe the trend for knocking down homes to make way for new, modern houses – apart from looking different – offers nothing more than months of noisy builders and a drastically changed street scene.

Just last week, Karen Buck, MP for Westminster North, called for Westminster Council to adopt more stringent guidelines, so neighbours do not feel helpless to contest the noise, dust and damage to their homes.

But these are the perceptible, tangible costs of subterranean building beneath homes and re- builds. What about the environment? The processes used to create the tonnes of concrete needed for basement extensions, as well as glass and other materials, have a carbon cost, as does transporting those materials to the site.

Highgate resident Richard Webber, of Broadlands Road, looked into the carbon cost of basements, after homes along his street had their cellars excavated to provide more living space.

What he found, shocked him. “When you look at the basements within 100 metres of my house, I think the total carbon emitted is equivalent to the saving made by Haringey’s refuse and recycling for three months,” he said.

Haringey has a 40:20 policy – an aim to reduce carbon emissions by 40 per cent by 2020. In theory, basements alone could wipe out any gains made by recycling, green energy and improved transport.

Many of the homes which are being knocked down are being replaced with so-called “eco-homes”. Even if new buildings are not eco-homes, Haringey and Camden demand all new-builds meet a high-standard of carbon efficiency.

But Gordon Hutchinson, Muswell Hill resident and visiting professor in sustainability systems at Bristol University, sees a fundamental flaw in this plan.

“A big household can emit three or four tonnes of carbon a year,” he explained. “If you went for an efficient refurb of that existing house, you would see it down to maybe two or three tonnes a year.

“The eco-house will emit less, maybe one tonne. That makes a difference of two tonnes a year – but when you have expended 50 tonnes building it, that means it takes 25 years to pay it back.”

This is not taken into account. Mr Hutchinson recently explained this to Haringey’s planning committee, which was deciding on whether to allow a house on Lansdowne Road, Muswell Hill, to be knocked down and rebuilt. His argument fell on deaf ears.

Mr Webber has found the same thing. He said: “[Planning decisions] are simply considered on aesthetics. When I asked planners why they didn’t take this into consideration, they say its another department’s responsibility. It vexes me that we go to great trouble to recycle cardboard, glass, paper, but when we have a house, we knock it down without thinking it could be recycled.”

Both would like to see the entire carbon cost of these developments taken into account by planning committees in future. Mr Hutchinson said: “The changes have to be now – it is too late in 2030.”

A Haringey Council spokesman said: “After the release of new planning information on environmental matters, we believe we are now in a much stronger position to provide detailed guidance to local developers on such issues.”