Campaigners fighting expansion at Heathrow Airport are claiming a victory over the Government after ministers agreed to publish a report which will show aircraft noise affects more people than previously thought.

Transport Minister Jim Fitzpatrick had previously said a consultation over expansion at the airport could go ahead without the results of the Attitudes to Noise from Aviation Sources in England report (ANASE).

However, at a meeting with the 2M group - a collection of councils representing 2million people living around the airport - he said it would be published, and announced the consultation would be delayed until December.

Speaking for 2M, Wandsworth Council leader Edward Lister, said: "Mr Fitzpatrick said the department would publish the report as close to Friday as possible.

"It was unthinkable that ministers could go ahead with the biggest expansion at Heathrow since Terminal Five without this.

"This is a victory for 2M and the local MPs and now we need to make sure that the findings are not dismissed but are used to reassess the impact of further expansion on people's lives."

The transport minister previously said: "We would not accept that the launch of the Heathrow consultation cannot proceed ANASE."

A spokesman at the Department for Transport did not accept there had been any climb down or that the ANASE findings would be integral to the consultation.

He said: "We always said we would start the consultation in 2007. People can make up their own minds about ANASE at the consultation."

The current measure of 57 decibels is used by the Government to define the level at which significant numbers of people start to become annoyed by aircraft noise.

The ANASE report will show a much lower threshold of annoyance - about 50 decibels.

If the report was adopted it could mean the area affected - currently about 258,000 people in a 117 sq km stretching from Windsor to Barnes - would rise 10 fold, including most of south-west London, Clapham Common and Battersea.

The Government's 2003 aircraft white paper stated expansion could only go ahead if there would be no increase in aircraft noise exposure as a result.

The current annual movement limit at the airport is 480,000.

The consultation is looking into increasing capacity by adding a third runway and allowing planes to take off and land on the two existing runways - known as alternation.

If both runway alternation were ended and a third runway built the number of flights each year at Heathrow could rise to around 800,000, equivalent to building a new airport the size of Gatwick.