An aide to Mr Cable defended his comments today, saying: “Vince is speaking for the whole of Britain. Boris is speaking for one city.”

The comments came as Nick Clegg indicated that the Liberal Democrats could be ready to abandon their pledge to oppose any airport expansion in the South East.

The deputy Prime Minister suggested that he had been persuaded by some of the arguments laid out in an Airports Commission report for a second runway at Gatwick airport.

However in their election manifesto in 2010 the Lib Dems promised to “cancel any plans for the third runway at Heathrow and any expansion of other airports in the south-east.”

This week an interim report by Sir Howard Davies, the head of the commission investigating where to build new runways in the South East of England shortlisted a second runway at Gatwick and two options to expand Heathrow.

Mr Davies said that airports would see growth in point-to-point flights where a passenger flies straight to a destinations rather stopping at a “hub” airport and catching a connection and suggested that a second runway at Gatwick would be a sensible way to meet this demand.

Discussing this section of the report on his regular call in radio slot on LBCV Radio, Call Clegg, Mr Clegg said: “I am the sort of person who generally tries to be led by the evidence … In his interim report he [Davies] actually makes some quite subtle arguments.”