Heathrow 'not right thing to do' - Johnson

Building a third runway at Heathrow Airport is not the right thing to do and risks fuelling a clamour for a fourth runway to be built in future, Foreign Secretary Boris Johnson says after the government approved the expansion.

Johnson, who was previously mayor of London, has been a vocal opponent of plans to expand Heathrow for years.

He sought and was granted permission to publicly oppose the government's decision on the issue.

"I do think that building a third runway slap bang in the middle of the western suburbs of the greatest city on Earth is not the right thing to do," Johnson said.

"What I worry about is that down the line, if and when a third runway were to be built, and I don't think it would be, but suppose it were to be, there would be an overwhelming clamour to build a fourth runway as soon as it was completed and then what would London be like?"

"You'd have New York, a city of beautiful skyscrapers, Paris, the city of light, London, the city of planes. Is that really what we want for our fantastic capital city?"