Mayor of London Boris Johnson claimed that Gatwick is the most likely destination for the UK's next runway because of a "political fix".
In a statement, Johnson said that despite Heathrow being the sensible choice for the Airports Commission, local residents' reluctancy over the noise factor is a serious stumbling block. But he added that Gatwick is "not the right answer".
"A lot of money is moving off Heathrow and on to Gatwick. Heathrow is closer to the answer but not deliverable. Gatwick is more deliverable but it is not the right answer," he said the Conservative mayor.
However, Johnson, who is in favour of a new airport being built on the Isle of Grain, east of London,said that Gatwick is the most likely destination, because "if there is a political fix to be done, it will be done".
"What is happening, I think, is a lot of the money is moving off Heathrow and on to Gatwick. It is perfectly obvious that if a political fix is to be done, it will be done in favour of Gatwick. That is where I think the parties are starting to get to," he said.
"Gatwick ... is not the answer, you don't get the connectivity, you don't get the hub. You don't future-proof London and the UK against the needs that will continue to grow.
"We are going to continue to need increasing [airport] capacity. All you will do by going for Gatwick is you will keep Heathrow as a brutally constrained hub which people fight to get into."
Johnson will submit further evidence to the Airports Commission in a bid to bolster the Isle of Grain's chances.
He said that if the commission, led by Sir Howard Davies, decides against the new hub, it will be "letting the country down".
Although the Boris-backed plans to create a new four-runway airport on the Isle of Grain could cost upwards of £80bn (€98.9bn, $134.8bn), backers say that the majority of it would be privately funded, creating thousands of jobs in the process.
A recommendation from the Airports Commission will not be made until after the general election in 2015.