The government is under growing pressure to re-think its support for a third runway at Heathrow and may delay a decision on the expansion which had been expected next month.
Any retreat would come as a fresh blow to airports operator BAA, which is poised to be broken up on the order of the Competition Commission, and to British Airways and other carriers at Heathrow.
Conservative leaders have already said they would reverse a decision to build a third runway, a growing number of Labour MPs have come out against and at least three senior cabinet members are reportedly opposed to the expansion, fearing it will damage the government’s environmental credentials and lose Labour support in the south-east.
Opponents point out there will be 2% fewer flights from Heathrow this winter than last year and a recent poll suggested a majority of the population oppose further expansion at airports.
A third runway would not be in operation before 2020 even if transport secretary Geoff Hoon gives the go-ahead – leading to reports that Labour may postpone the decision and leave it up to the next government.