Former deputy prime minister Nick Clegg has urged the government to choose Gatwick expansion despite the Davies Commission recommending a third runway at Heathrow.
Writing in the Evening Standard, Mr Clegg warned prime minister David Cameron that great swathes of voters in south-west London would not forgive him if Heathrow were to get the go-ahead.
"Gatwick has a dedicated, unpopulated site that is ready to go," said the former Liberal Democrat leader.
"Gatwick claims with some justification that it can get cracking with the development with less risk of delay than its Heathrow rivals.
"Given that a government decision in favour of Heathrow will be followed by a contentious debate and vote in parliament, then a public inquiry, the potential for further interminable delay is strong."
Mr Clegg also said Gatwick posed a lower pollution risk and that there was little to chosses between the two airports on point-to-point travel.
He added: "The technocratic consensus, especially in the Treasury, is robotically in favour of Heathrow.
"But this ignores the unavoidable reality that planes are forced to fly low over one of the most built-up urban connubations in the world.
"If we were starting from scratch, there is simply no way that we would choose to build a new airport there."