Policy chief warned Cameron over Heathrow air quality plan
David Cameron was warned a year ago that the Government was "exposed on Heathrow" because it had no answers to concerns on air quality.
A memo to the then PM by his Number 10 policy chief raised alarm about a Whitehall air quality plan, according to The Guardian.
The note, written by senior adviser Camilla Cavendish, was dismissive about the first draft of a government air quality initiative from the department of environment which was then headed by Liz Truss.
The September 2015 memo said: "There are three problems with Liz's clean air plan as currently written: First it is still very much a draft which quotes initiatives that are likely to be abolished ... Second it both overclaims and underwhelms.
"It says we want the cleanest air in the world but does not even begin to tackle the fundamental question of how we might help people to shift away from diesel cars. Third, it leaves us exposed on Heathrow where we don't yet have an answer on air quality."
The revelation came after Theresa May defended her approach to expanding airport capacity after it emerged a final decision by Parliament would not be taken until the winter of 2017/18.
The Prime Minister said a judgment would be made this month on whether to go ahead with a third runway at Heathrow, as the airport insisted there had been "no delay" over the plan.
She said she would settle an issue that politicians had been wrangling over for decades, but the "formal process" would mean a further consultation before a vote by MPs.
Mrs May told the Commons at Prime Minister's Questions: "This is a subject that has been debated, discussed, speculated on for 40 years. This Government will take a decision.
"But there is then a formal process that has to be undertaken so that the Government will identify its preferred option of site. That will then go to a statutory consultation.
"The Government will then consider the results of the statutory consultation and bring forward an airports national planning statement on which this House will vote."
The Davies Commission recommended a third runway at Heathrow, but Mrs May stressed that the other two options in the report - expanding Gatwick or lengthening an existing runway at Heathrow - were "credible and deliverable".