The battle over London’s airports has intensified after the capital’s mayor backed plans to build runways on an artificial island in the Thames.

Boris Johnson reaffirmed his opposition to plans to build a third runway at Heathrow by calling for a new airport to be built two miles off the Kent coast, near Sheppey.

The mayor’s planning team, led by Kit Malthouse, has brought back the idea which first surfaced when the initial consultation was launched into London’s airports.

It would see Heathrow closed and replaced by a 24-hour hub with rail and ferry links, at a cost of up to £40bn.

Malthouse said: ‘I think it’s madness to expand any of the other airports when there is an obvious solution elsewhere.’
But the airline industry condemned the idea, and environmentalists warned it would destroy protected widlife areas.