The government's own sustainability watchdog has cautioned against making any decisions on airport expansion until clear policies are in place.

The Sustainable Development Commission  - set up by Labour to advise on disputes over environmental issues - says there is 'considerable disagreement' about the evidence the government uses to inform decisions.

In its report, ‘Breaking the Holding Pattern’, it recommends the creation of a special independent commission and a revision of air transport policy. 

Hugh Raven, Commissioner at the Sustainable Development Commission, said: "Until some basic questions are answered, we cannot be in a position to make decisions about the future of air travel. The government must live up to its commitment to listening to citizens and stakeholders, and act to ensure we make the best possible decisions for everyone involved."

But the Department of Transport said it was not viable to wait any longer for a decision on Heathrow.