Ministers 'are sneaking through' Heathrow plan

The report, for the Department for Transport, undermines the case for building a third runway at the airport.

But the Aviation Minister Jim Fitzpatrick rejected calls to publish the research early in a letter to the local authorities around Heathrow.

The study, called The Attitudes to Noise from Aviation Sources in England (Anase), concludes that the existing method of measuring aircraft noise is too narrow and outdated and fails to take into account the huge increase in flights at Heathrow.

The report says people today have higher expectations of a peaceful environment, so are more annoyed about noise than 25 years ago.

Aircraft noise causes most annoyance to people on higher incomes, those in the social groups A and B and those aged 35 to 64, yet current methods fail to take that into account.

In the 2003 aviation White Paper the Government pledged that a third runway would only go ahead if there was "no net increase" to the size of the area around Heathrow affected by 57 decibels of aircraft noise.

That was the level deemed to cause "significant community annoyance", but the new study indicates a level of around 50dB would be more realistic. Around 258,000 people live in the 57dB area around Heathrow, but ten times that number live inside the 50dB area.

A spokesman for the 2M group, made up of the 12 local authorities that represent the two million people living under Heathrow's flight paths, said: "It is outrageous for the Government to hide this study, which reveals how the impact of aircraft noise has been seriously underestimated.

"They are trying to sneak through the third runway consultation without giving the public the full facts."

But Minister Fitzpatrick said the study had yet to be finalised. He wrote: "It would be premature to suggest that the report will lead to any change in approach - we shall want to reflect on it. We would not accept that the launch of the Heathrow consultation cannot precede Anase."

The study was ordered six year ago by the then Aviation Minister Bob Ainsworth. At the time he said: "This study underlines the Government's commitment to underpin our policy on aircraft noise by substantial research that commands the widest possible confidence."