Does London need a new airport?

(From Guardian Unlimited)

David Cameron has given the green light to a consultation on a new airport for London, based on plans put forward by the London Mayor Boris Johnson for a new "hub" in the Thames Estuary. The project is already being dubbed "Boris island" .

A planned announcement earlier this month was reportedly delayed after an intervention from the Liberal Democrats, whose official policy is to oppose airport expansion on environmental grounds. The Telegraph has the full details of the coalition tensions around the subject here .

London already has Heathrow, Gatwick, Stansted, Luton and City airports. Does London -- and the country -- actually …