UPDATE: Boris Johnson appeared on Newsnight on Tuesday (video above) to defend his position against the expansion of Heathrow, calling it a "sham, a snare and a delusion".
Boris Johnson has attacked proposals to build a third runway at Heathrow as "completely crackers", after a government-appointed commission chose the west London airport as one of its expansion options.
In an interim report published today, the Airports Commission, headed by former Financial Services Authority chief Sir Howard Davies, also put an extra, second, runway at Gatwick airport in West Sussex on to its short list.
The mayor of London, who favours the construction of an entirely new airport in the Thames Estuary, told BBC Radio 4's Today programme: "Why on earth entrench a huge planning error and expand Heathrow and consign future generations to misery when we could go for the right option?"
"This is an argument, I believe, that will eventually be won by the iron logic of the case which is that you cannot continue to expand a 21st century hub right in the middle of the western suburbs of the greatest city on earth."
The commission has kept the door open for a Thames Estuary airport scheme, but the plan was not one that made it onto the short list. Boris insisted Sir Howard's concerns about an estuary airport could be addressed.
"I don't think it costs anything like as much as I think he has been saying. We think that the transport infrastructure alone comes in at about £20 billion, then you have got the cost of the airport but that, we think, is relatively easily financed by international investment."
The last Labour government supported a third runway at Heathrow but expansion at the west London airport was ruled out by the coalition government when it took power in May 2010.
But transport secretary Patrick McLoughlin has said the coalition's pledge was not to build a third runway "in this parliament", suggesting the Conservatives would pledge to build one after 2015.
On Tuesday morning Vince Cable insisted the Lib Dems were still firmly opposed to expanding Heathrow.
"The Davies Commission interim report has put Heathrow at the front of its thinking which is questionable economically, damaging environmentally and probably undeliverable politically," he said.
The business secretary, whose Twickenham constituency is in West London, said "pushing ahead with Heathrow expansion is almost certainly the worst option for expanding airport capacity".
He added: "My strong view is that the Davies review should not decide to press ahead with Heathrow options and I will be making that view known in the strongest terms."
Last week, Tory MP Zac Goldsmith said any decision by the prime minister to back Heathrow expansion would represent an "off-the-scale betrayal" and David Cameron would "never be forgiven in west London".
The Richmond MP told BBC Newsnight last week that if the government changed its position and supported the expansion of heathrow he would quit as an MP and trigger a by-election. "I wouldn't stand as a Conservative," he said.