The figure for carbon dioxide, taken from an Environment Agency report, represents 40 per cent of the emissions from Welbeck landfill site. The remaining 60 per cent is methane – which is 21 times more harmful to the environment.

But site operators Welbeck Waste Management Ltd (WWML) want to increase waste capacity at the tip, which is the largest in Europe.

An Environment Agency report from December 2006 said: ‘It is apparent that uncontrolled gas emissions from the site may be making a significant contribution to the UK’s carbon emissions’.

And three further reports highlighted breaches of the site permit because of gas emissions. One, from September 7, said measures were ‘woefully inadequate’ to deal with the problem.

Action group Residents Against Toxic Scheme (RATS) claims nothing has been done to stop the gas escaping in the past 12 months. And members say the Environment Agency has refused to prosecute.

President Paul Dainton said: “The local population are extremely frightened and worried about the effects. We first complained in 2003. After 10 years of the tip being opened, they have not improved the monitoring systems. The Environment Agency seems to be totally incapable of making the system work.”

He said plans to build a generator to burn off gases at the site were part of the original plans, but had been shelved by the operators. And a recent attempt by the operators to vary the site permit would increase waste capacity at the site, altering the landscape for many years.

He said: “They just want to get more tipping space. It will be nearly 20 metres higher than it should be – it’s just unbelievable. The levels we have got now were agreed two years ago.”

A spokesperson for Welbeck Waste Management Ltd (WWML) said it was working with the Environment Agency to address concerns about the emissions. A spokesperson said there was no threat to human health from operations at Welbeck.

“Suggestions that huge volumes of gas are being emitted into the atmosphere are based upon the difference between predicted gas emission levels from a mathematical model and the actual levels of gas collected at the site. In this instance, actual gas levels recorded are far below the models predictions.”

The spokesperson said installation of the gas generator was ‘predicted’ for 2008.