A third runway would have a 'broadly neutral' impact on Heathrow's nearest neighbours,the Airports Commission has concluded.

More jobs and better transport links would balance out the negative impacts of expansion like noise and congestion, it says.

The commission's latest assessment of rival proposals to expand Heathrow and Gatwick was published this morning, as members of the public were invited to have their say in a three-month consultation.

For the first time the group has said how its own analysis differs from the claims made by the different bidders, including the estimated cost and the impact on people living under the flight paths.

Cost of a third runway

The main difference is in the estimated cost, with all schemes coming with a much heftier price tag according to the commission.

It forecasts a third runway at Heathrow would cost £18.6 billion, compared to the £14.6bn predicted by the airport. Extending the northern runway would cost £13.5bn (£10.1bn) and a second Gatwick runway would cost £9.3bn (£7.4bn).

Significantly it predicts the cost of building a third runway would saddle Heathrow with a £29.9bn debt - bigger than that of the National Grid - and would see landing charges shoot up from £20 per passenger to a peak of £32 to cover the cost. Heathrow estimates these charges would rise to £27 before returning to current levels by 2050.

Noise and pollution

On the environment, the commission supports Heathrow's claim that a bigger airport would subject fewer people to noise than at present due to quieter planes. It also forecasts a significant decrease in night time disturbance but says overall noise would be higher in 2030 with a third runway than without.

The commission also states that there is 'clearly a substantial negative impact of the scheme on air quality, unless forceful mitigation measures are implemented'.

Overall, the document concludes: "For those within 5km of the airport, the commission's quality of life analysis suggests that the 'bundled impact' is likely to be broadly neutral, with the positive impacts of the airport (such as transport connections and jobs) and the negative impacts (such as noise and congestion) balancing each other out in quality of life surveys."

It adds that the scheme would improve quality of life at national level, due to better connections and the 'economic and social benefits'.

The consultation is due to run until February 3. The Airports Commission will make its final recommendations next summer, after the general election.

REACTION TO THE COMMISSION'S REPORT

Heathrow highlighted the commission's findings that a new Heathrow runway would boost the economy by £112-211bn - up to £97bn more than from expanding Gatwick.

It also flags up the report's conclusion that expanding Heathrow could deliver 179,000 new jobs by 2050 - 130,000 more than building a second runway at Gatwick - as well as the findings on noise.

Heathrow chief executive John Holland-Kaye said: "This shows that Heathrow's proposal is deliverable and is the only way to keep Britain at the heart of the global economy.

"Now it's time for all those who want a better future for Britain to make their voice heard and back Heathrow."

Gatwick said the report showed 'momentum is building' behind its case for expansion.

It was keen to highlight the commission's findings on the need for additional 'hub capacity' - an airport acting as a transfer point for major global destinations.

The need for a hub airport has always been a big part of Heathrow's argument, as it claims it is the only airport which can provide this, but the commission concluded there was not a 'binary choice' between increasing hub capacity and providing more direct 'point-to-point' flights.

Gatwick also highlighted how the numbers affected by aircraft noise under its plans were significantly below those impacted by an extra runway at Heathrow.

Its chief executive Stewart Wingate said: "The Airport Commission's consultation published today underlines why momentum is gathering behind Gatwick's case for airport expansion in the south east.

"The commission will have to consider a range of factors in making their final decision. Their report today indicates why expansion at Gatwick best answers all the questions. It can give the country two world class airports."

Heathrow Hub , the company proposing to extend the northern runway at Heathrow, said the report backed up its claims that its proposal was the cheapest way to expand the airport and would not significantly affect any new communities with aircraft noise.

Jock Lowe, the longest-serving Concorde pilot and the man heading up Heathrow Hub, said: "We welcome the launch of this public consultation process by the Airports Commission. We believe we have an innovative solution to Heathrow expansion and that the British public, given a chance to consider our proposal in some detail, will agree that our approach offers the UK the best possible answer to the growing aviation capacity challenge that we all face."

HACAN , the anti-Heathrow expansion campaign group, said the report suggested expansion at either airport was viable, meaning it came down to a straight choice on the number of residents affected.

Its chairman John Stewart said: "Both Gatwick and Heathrow are very much in the running. At the end of the day it will come down to political deliverability. A new runway at either airport would boost the economy but the report underscores the fact the noise at Gatwick would affect far fewer people. For politicians, that could be the clincher."

Back Heathrow , the pro-expansion pressure group, said: "Communities around Heathrow now face a clear choice. The commission's independent analysis shows expansion will create up to 41,000 jobs at Heathrow by 2030, but without growth there could actually be 14,000 fewer airport jobs."

Hounslow Council leader Steve Curran said: "We remain determined in our battle for a better not bigger Heathrow.  This means better protection from noise now for our schools and thousands of residents who live under the flight path."

Responding to the commission's higher estimate of the building costs involved, he added: "The costs for better protection from noise pollution needs to be part of the equation too."