The economist tasked with solving Britain's air capacity has said the South East needs new runways - adding pressure to calls for a hub in the Thames estuary.

Sir Howard Davies made the announcement today as he gave the first indication of the Airports Commission's findings.

The group will make a shortlist in December from more than 50 proposals, including several in the Thames estuary.

Speaking today, however, Sir Howard rejected calls to expand other regional airports instead of those around London.

This will be a blow to Medway politicians, who heavily supported expanding Birmingham Airport.

Almost every mainstream politician in north Kent has spoken out against an estuary airport, saying it would cause untold environmental damage.

Councillors and MPs visited Birmingham Airport for a fact-finding mission and met its directors earlier this year.

Yet Sir Howard said despite the new High Speed 2 line improving journey times, the draw of London was too great.

"On average, a resident of Greater London takes 2.5 flights a year, compared to just over 1.5 for the country as a whole," he said, which included holidaymakers as well as businessmen.

"This will always make it an attractive market for airlines, even before you take into account the significant projected population growth in the region."

Sir Howard said the government, not just private investors, will need to fund new infrastructure.

He did not rule out closing existing airports to open new ones - a possible reference to the architect Lord Foster, who would build a four-runway airport on the Isle of Grain and close Heathrow to compensate.

Other options in the estuary include airports at Cliffe and off the coast of Sheerness.

"Our final conclusions will not please everyone, I am sure," said Sir Howard.

But he added: "An attempt to rely only on runways currently in operation would be likely to produce a distinctly sub-optimal solution for passengers, connectivity and the economy."

Other expansion plans in the south east include new runways at Heathrow, Gatwick and Stansted.

Rochester and Strood MP Mark Reckless, who had a meeting with Sir Howard two weeks ago, insisted Birmingham was a good choice.

He said: "With High Speed 2 it would be very accessible to London and it's right in the middle of the national motorway network."

But he added: "It wouldn't have been the whole solution. As well as Birmingham I also went to Gatwick and looked at better transport connections to Stansted."