In early 2007 the prospect of a third runway at Heathrow seemed doomed. Research commissioned by the government revealed that the expansion would breach noise and pollution targets, making life even more unpleasant for the long-suffering residents under the flight paths.

The results were particularly depressing for David Gray, the senior civil servant in the Department for Transport (DfT) who was charged with showing how the runway could be built without any extra impact on the environment. However, he was then offered a lifeline.

On February 9 an e-mail appeared on Gray’s computer screen from BAA, the airports operator, which had been quietly passed the confidential findings by the DfT.

Headed “reforecast”, the e-mail suggested that the government dump the initial damaging findings and recalculate the environmental impact on residents using new figures largely provided by BAA.

Documents seen by The Sunday Times show that over the next weeks and months, senior executives from the airports operator were given unrivalled access to Whitehall so they could select alternate input data for the environmental predictions until they got the right results.

These frantic efforts finally resulted in success. The joint endeavours of the government and BAA claimed to prove that a new airport the size of Gatwick could be bolted on to Heathrow without any adverse environmental impact.

The conclusion in the third runway consultation document published last November was either an environmental miracle – or a mirage.

“These documents show it was quite clearly a fix,” said Justine Greening, MP for Putney in southwest London and shadow Treasury minister, who obtained the papers using freedom of information laws. “BAA’s involvement was completely inappropriate and should now be properly investigated.”

Greening will write this week to Ann Abraham, the parliamentary ombudsman, calling for her to investigate the research used in the consultations. London councils opposed to the runway also want an inquiry into the scale of the “collusion and collaboration” between the government and BAA.

The new disclosures will raise questions over the forthcoming decision on the third runway and the lobbying links between BAA and the government. Tom Kelly, Tony Blair’s former Downing Street spokesman, is now BAA’s director of public affairs; several senior Labour figures have lobbied or worked for the airports operator, which is now owned by Ferrovial, the Spanish conglomerate.

The consultation process is confirmed to have been weakened by a submission from the government’s own watchdog, the Environment Agency. It has unpicked the DfT document and concluded that it is not “sufficiently robust” to support the construction of a third runway.

The new runway has been on the starting blocks for years. The government first came out in favour of it in a 2003 white paper, but insisted that strict environmental targets should be met. These stated that there should be no increase in aircraft noise – using 2002 as a bench-mark – and that new European air quality limits on nitrogen dioxide should not be breached.

The Project for the Sustainable Development of Heathrow – or “Project Heathrow” – was created in the DfT to try to clear these hurdles. Predictably, the initial results obtained by Gray showed that a third runway would mean a lot more noise and extra pollution.

The results were unacceptable to BAA, which was determined to maintain its dominance of British airports. Minutes of a meeting held in January 2007 between company executives and DfT officials show discussions about a possible “ratcheted down” forecast on the environmental impact. Gray subsequently sought advice from BAA on what data might be “stripped out to achieve compliance”.

Government meetings were held in BAA offices and DfT minutes written up on the company’s headed notepaper. One disillusioned official who was involved in Project Heathrow said: “It’s a classic case of reverse engineering. They knew exactly what results they wanted and fixed the inputs to get there.”

The BAA e-mail to Gray in February came from a senior executive, whose name is blanked out in the documents, and outlined the measures required to change the criteria for a “reforecast”.

One of the solutions was to change BAA’s predictions of the predicted airline fleet at Heathrow in 2030. The new forecasts were filled up with much quieter planes. It was still not enough, so BAA curbed the number of flights used for researching the noise footprint until the environmental target was met.

A Civil Aviation Authority document states: “The BAA forecast was scaled back to such a point where the contour would meet the white paper test.”

It was shaky science because BAA’s forecasts are unreliable. In the mid1990s the airports operator had wrongly predicted the demise of smaller aircraft; when lobbying for terminal 5 it had predicted 453,000 flights at Heathrow by 2013 – a figure that was reached in July 2000.

However, fixing the noise footprint was relatively straightforward compared with the air quality problems. There were predicted to be “hot spots” around Heathrow if a third runway was built which would breach European Union laws.

A BAA “surface access” report considered radical measures which could help to bring down the forecasts – including a “shroud” over the M4 with “air scrubbing” devices, diverting cars around “air quality” hot spots and tolls.

The problem was finally solved with a giant leap of faith. It was confidently predicted that car engines would be so clean by 2030 that there would, in fact, be no extra pollution.

DfT officials also helped to curb predictions about the extra carbon emissions generated by the airport. They concluded that over a 60-year period the additional flights on the third runway would generate an extra 181m tons of carbon dioxide. But they decided to exclude international flight arrivals from the calculations, which was last week described as “beyond ridiculous” by opponents to airport expansion.

The documents show the DfT was even prepared to redraft the consultation paper with additional comments included from BAA. The company’s unprecedented control over the consultation document will now put pressure on Ruth Kelly, the transport secretary, to commission an independent scientific report on the impact of the third runway. It also underlines the close relationship between BAA and Labour.

One of the main lobby groups campaigning for the third runway is Future Heathrow whose campaign director is Lord Soley, a former chairman of the parliamentary Labour party. The launch of the group was attended by Alistair Darling, then transport secretary.

Labour’s small army of public relations experts and special advisers regularly move between Whitehall and BAA. In addition to Kelly’s role on BAA’s executive committee, Joe Irvin, now a special adviser at Downing Street, was a former director of public affairs at BAA. Another former director of public affairs at BAA was Stephen Hardwick, who was also a former policy adviser to John Prescott.

These links will come under new scrutiny as the key figures and assumptions used in the third runway consultation document are examined. The official response of the Environment Agency – passed last week to The Sunday Times – warns that the potential risk to public health has not been properly assessed.

Its response states: “We do not think the evidence presented is sufficiently robust to conclude that the proposed Heathrow development will not infringe the [nitrogen dioxide] directive, bearing in mind the uncertainties that need to be addressed.

“We do not contend that the evidence does not exist to support the case for meeting the air quality requirements, but that, as presented in this consultation, the case is not made.”

The agency adds that even if the EU directive is met, the consultation fails to consider the wider impact of other pollutants on public health.

It suggests that it may be better to postpone expansion rather than go ahead. “There are arguments for postponing irreversible investment decisions in the face of uncertainty,” the report says.

BAA last week denied collusion. It said the DfT was responsible for the research although BAA had provided some of the original data. The DfT – which is expected to announce its decision on the third runway in the summer – said that BAA had been required to play a significant role in the consultation papers because it had valuable data that were needed.

However, John Stewart, chairman of Hacan ClearSkies, the lobby group opposed to Heathrow’s expansion, said: “The government is being told by its own chief environmental advisers that the figures and assumptions on which the consultation has been based are flawed, misleading and contain huge holes.”

Heathrow documents released under Freedom of Information act: Doc 1 / Doc 2 / Doc 3 / Doc 4

Leaked Environment Agency response to Heathrow consultation

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