Residents in south west Hertfordshire could find themselves living under a flight path if the proposed third runway at Heathrow Airport gets the go ahead.

Rickmansworth in particular was highlighted as being in a noise disruption area that would be created by planes approaching Heathrow’s third runway according to an investigation by anti-expansion campaign group 2M Against Heathrow Expansion.

Residents in the town have reacted with frustration to the news that they could suffer a "significant impact" from the noise of planes passing overhead as early as 4.30am.

Rickmansworth councillor and chairman of Rickmansworth Neighbourhood Forum David Sansom said: "We had this a couple of years ago and there was a lot of strong feeling against it from the community.

"Two years ago we all combined to have them change what they were doing.

"Because Rickmansworth is in a valley the noise would echo.

"I am sure as far as Heathrow is concerned this is a mostly green area and don’t think people will complain.

"But I don’t think they quite understand how it works in a valley, if aircraft are going right down the middle the noise is something that will concern us."

The 2M group, which includes 24 councils in West London and the Home Counties but does not currently feature any authorities in Hertfordshire, has spoken out strongly against the plan.

Councillor Ravi Govindia, spokesman for 2M and leader of Wandsworth Council, said: "Across London and the Home Counties a total of three million people would be living under its flightpaths. The price is far too high.

"Heathrow is in the worst position in the country for a major airport and the Government should focus the search for new runway sites on viable settings where the impacts are less severe."

But leader of the council Councillor Ann Shaw said the report was nothing for Three Rivers to consider at this stage.

She said: "For years things have been proposed every two or three years but we are not going to worry people when there is nothing to worry about."

Councillor Shaw added she would want to know more about 2M before Three Rivers became involved with the group.

Kevin Snow, a Three Rivers District Council spokesman, said: "We would expect to be formally consulted if any changes to Heathrow Airport in the future were to have any noise impact on Three Rivers residents."

The Davies Commission is due to deliver its interim report into airport expansion later this year and will conclude in 2015.

At a conference last year former British Airways chief exec Willie Walsh said he did not believe a third runway would ever be built at Heathrow.

He told the conference "my personal belief that a third runway will never be built" and that "we are planning for life without it."

Heathrow Airport described the new noise map as scaremongering and denies a bigger airport would cause problems.