As I described in an earlier post, the government expects to breach the limits in the EU air quality directive in 2010, before it uses “mixed mode” operation to add an extra 60,000 Heathrow flights a year by 2015. It has indirectly admitted that this expansion depends on delaying the directive for those five years, while denying any causal connection.

This position insults not only our intelligence but that of EU environment commissioner Stavros Dimas, whose permission is required. Any state seeking a delay on the grounds that it cannot comply by 2010 must put forward a plan showing how it intends to comply subsequently. Two weeks ago, Chris Smith, chairman of the Environment Agency and a former Labour minister, made a point that must have occurred to Dimas:

“How will the further expansion of Heathrow, and the inevitable and detrimental consequences on air quality and emissions, help in meeting a target that it is predicted we will exceed?”

As one expert told me, for the government to assume that a delay will be granted is quite arrogant. The government has further insulted Dimas’ intelligence with its account of “plans and programmes” to address breaches of existing rules. Astonishingly, the Department for Transport’s (DfT) submission, on which it has just finished a consultation, does not mention an imminent increase in pollution from Heathrow.

Just as arrogant is the DfT’s apparent intention to ignore “residual exceedences” of the pollution rules in 2015, the latest date by which the directive will be in force. Its risk register documents, obtained by Greenpeace under the freedom of information act, show that officials doubted whether proposed mitigation measures would be politically acceptable, as well as whether they would be “justified for a relatively short period before things improve over time”.

The suspicion that Britain will simply flout the rules has caused Dimas to speak out twice this week. On Tuesday, the Standard quoted him as warning Britain not to try to fudge it. In my piece for newstatesman.com yesterday, Dimas went further, suggesting that he would take action to enforce the rules if Britain allows them to be breached.

The more immediate threat to Heathrow expansion from legal action covers the proposed third runway (from 2020) as well as mixed mode. Because there exists a clear paper trail showing that airport owner BAA helped DfT “reforecast” its projections on pollution and noise, the government will convince no-one if it claims to have met the conditions for expansion set out in its 2003 white paper. Local authorities are already threatening legal action and must be as confident as the government is worried by the prospect.

So pollution could be the first stumbling block for Heathrow expansion, even though DfT officials predicted that noise was “likely to be the key constraint for R3 in 2020”. We certainly mustn’t forget noise. Last week Environment Secretary Hilary Benn answered a parliamentary question on air quality from anti-expansion MP John Grogan:

“I have regular discussions with ministerial colleagues about air quality and noise in relation to transport, including plans around Heathrow.”

Grogan hadn’t mentioned noise. Was Benn trying to tell us something?

Chris Ames, a freelance writer and investigative journalist, is editor of iraqdossier.com