Boris Johnson: Third Heathrow runway 'would be crackers'
17 December 2013 Last updated at 09:31 GMT
The Airports Commission has short-listed its three options for expanding the UK's aviation capacity.
These include adding a third runway at Heathrow, lengthening an existing runway at Heathrow, and introducing a new runway at Gatwick.
The commission has also decided not to rule out the possibility of a new airport in the Thames Estuary, favoured by London Mayor Boris Johnson.
Speaking to the Today programme, Mr Johnson said that he does not believe this fourth option would cost as much as critics have suggested.
He said the expense of building the airport could be "relatively easily financed by international investment".
The mayor of London also described the addition of a third runway at Heathrow as "completely crackers" and "wrong for the country".
"As soon as you've completed a third runway - which wouldn't be until 2030 at the very earliest - there will be insatiable demands for a fourth runway.
"It would be catastrophic for quality of life... you'd be consigning millions of people to extra noise pollution."
A final report from the commission is due by the summer of 2015.
First broadcast on BBC Radio 4's Today programme on Tuesday 17 December 2013.