The Department for Transport commissioned the study in 2001

The number of respondents at least "very annoyed" generally increases in areas above 43 decibels, the study for the Department of Transport found.

With current noise restrictions at 57 decibels, noise disturbs two million more people than previously estimated.

But aviation minister Jim Fitzpatrick said the figures were not "robust" enough to lead to a change in policy.

The Attitudes to Noise from Aviation Sources in England (ANASE) study, commissioned six years ago by ministers, could undermine plans to build a third runway at Heathrow.

It questioned 2,733 residents in the first major aircraft noise study since 1985.

Annoyance 'consistently greater'

It found that levels of annoyance at Heathrow noise were "consistently greater" than they were 27 years ago.

The Anase study also found that people began to be significantly disturbed at lower levels of noise.

An estimated 258,000 residents currently experience Heathrow noise levels of 57 decibels or above, the level at which the government begins to place restrictions upon noise.

However, a further two million residents, including people living as far afield as Clapham, Richmond and Maidenhead, experience noise levels above 50 decibels.

We have already said that any expansion of Heathrow must not increase the area where people experience the highest noise levels Aviation minister Jim Fitzpatrick

The Anase study also found that people were significantly more annoyed by aircraft noise before 0700 GMT or after 2300 GMT.

Mr Fitzpatrick said the study "gives us a better understanding of the complex issues surrounding aircraft noise".

"But as the peer reviewers make clear, it does not give us the robust figures on which it would be safe to change policy," he added.

The government is due to begin its consultation on plans to build a third runway at Heathrow next year.

"We have already said that any expansion of Heathrow must not increase the area where people experience the highest noise levels, and this will be fully considered in the forthcoming Heathrow consultation," Mr Fitzpatrick said.

The study confirms exactly what residents living under Heathrow flight paths have been telling the government for a decade John Stewart, Heathrow Association for Control of Aircraft Noise

John Stewart, spokesman for campaign group the Heathrow Association for Control of Aircraft Noise, said the Anase study was "embarrassing" to the government.

"It shows that they have been seriously underestimating the number of people affected by aircraft noise," Mr Stewart said.

"The study confirms exactly what residents living under Heathrow flight paths have been telling the government for a decade."

If the government accepted the findings of the study, it would "throw a huge spanner in the works" of plans for a third Heathrow runway, Mr Stewart said.

"It would be a scandal if the Department for Transport does not act upon these findings."