An aerial image of the Thames Hub airport, designed by Lord Foster.

by Martin Jefferies

Kent passengers will pay more to fly unless new airport runways are built in the south east, the aviation regulator has warned.

In a report published today, the Civil Aviation Authority (CAA) says additional capacity would offer "significant benefits" for consumers and the economy.

It said improving facilities at existing airports, such as Manston, would be a "short-term" fix, but claimed new runways are needed to maintain the UK's direct access to global markets.

The CAA's comments will put more pressure on the government to explore building a new airport in Kent - possibly in the Thames Estuary or on the Isle of Grain.

Andrew Haines, chief executive of the CAA, said: "As we haven't built a single runway in the south east capable of handling Boeing 747s and Airbus A380s for over 70 years, the difficulty of increasing capacity is obvious.

"The challenge facing the government is to create an aviation policy that stands the test of time - not a policy for five years but one that lasts 30 years.

"If the private sector is to have sufficient confidence to deliver additional capacity then it needs to be convinced that government policy is based on robust evidence and is likely to last for at least a generation."

Two options for an airport in Kent have already been put forward.

The Mayor of London Boris Johnson favours an airport constructed on artificial islands - a scheme dubbed 'Boris Island'.

World-renowned architect Lord Foster's plans for an airport on the Isle of Grain are more advanced.

He has already released artists' impressions of how the £50bn airport - capable of carrying up to 150m passengers a year - could look.

In November, Chancellor George Osborne said a new airport in the south east could form part of a series of major infrastructure projects that would galvanise the economy.

However, he stopped short of announcing Kent as the government's preferred location.