The ghost of Concorde has been enlisted to help to justify a third runway at Heathrow and an extra 500 flights a day over London.

The supersonic fleet was withdrawn and sent to museums in 2003, but it is being included in the Department for Transport’s comparisons for noise levels at the airport. The Government has pledged that the area blighted by 57 decibels, known as the 57 decibel contour, will be no greater than in 2002, the last full year of Concorde flights.

This will make it much easier to approve the new runway because Concorde was by far the loudest aircraft operating out of Heathrow. One Concorde flight produced as much noise disturbance as 120 Boeing 757s, according to the DfT’s method of calculating noise.

The 57 decibel contour — so named because that is the level at which the DfT deems noise to be a nuisance to residents — covered 49 square miles (127 sq km) in 2002 but has since shrunk by more than 4 square miles and is likely to carry on shrinking as quieter aircraft are introduced. The number of people living inside the contour has fallen by more than 20,000 since 2002.

The new runway, which could open by 2017, would increase noise disturbance greatly, but the Government would be able to claim it was only as bad as in 2002.

Residents living under Heathrow’s flight paths argue that this is unfair because there were only two Concorde flights a day — one take-off and one landing — but they will be replaced by dozens of modern aircraft. Noise from Concorde used to reach more than 100 decibels for those living close to the airport. John Stewart, chairman of the Heathrow Association for the Control of Aircraft Noise, said: “It is absurd to use an ear-splittingly noisy aircraft now lying in museums in the standard used to determine whether Heathrow can be expanded.

“The Government should, at the very least, be pledging that there will be no more disturbance than there is now. Instead, they are trying to dupe us with a worthless benchmark relating to the situation five years ago.”

Mr Stewart said that many residents had tolerated the noise created by Concorde because it lasted for only a couple of minutes and the delta-winged aircraft provided a great spectacle. “But it will be replaced by the non-stop drone of aircraft every two minutes. It is the regularity of the flights that causes the problem, but the Government is failing to take this into account.”

A report on aircraft noise by the Department for Environment, Food and Rural Affairs in 2004 found that Concorde had a “distorting effect” on the setting of noise limits for Heathrow.

It said: “Concorde movements, despite being relatively infrequent compared to other aircraft types, have a dominating influence on the shape and size of the noise contours for Heathrow Airport.”

The report added that a more accurate assessment of the disturbance caused to residents could be obtained by excluding Concorde flights from the calculations.

The DfT published the results of a six-year study into aircraft noise last week. It found that noise causes far more annoyance than previously thought and concluded that the method of calculating noise, adopted a quarter of a century ago, was too narrow and failed to take account either of the huge growth in the number of flights or the public’s growing intolerance of noise.

The study also found that the public began to be significantly annoyed by aircraft noise when it reached 50 rather than 57 decibels.

There are 258,000 residents inside the 57-decibel area, but ten times that number live inside the 50-decibel area.

The Government has refused to take the research into account in the debate over the third runway because it claims that there is still no consensus about what level of noise constitutes a serious problem.

Jim Fitzpatrick, the Aviation Minister, has told local authorities around Heathrow that he expects to publish proposals for expanding the airport towards the end of next month.

As well as the third runway, the Government will propose ending the current system of runway alternation which gives residents half a day’s respite from aircraft approaching over their rooftops.

The two existing runways could accommodate an extra 60,000 flights a year if they were used for take-offs and landings throughout the day.

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