Key to our prosperity doesn't lie in Heathrow

Willie Walsh, chief executive of British Airways, said in these pages last week that only a third runway at Heathrow can preserve London's "world-class business status".

"London's air network is shrivelling," wrote Mr Walsh. With Heathrow congested, delay-prone and offering 180 destinations, down from 227 in 1990, "continental hubs such as Frankfurt have raced past us [and] fancy their chances of stealing London's business crown".

But if achieving the business crown of Europe was about having good airports, Frankfurt or Paris would have won it years ago. Instead, even as they've streaked ahead of London in runway capacity, both Frankfurt and Paris have fallen further behind in their share of global commerce. In London, there might be more barriers to getting through the airport. But there are fewer barriers in things that really matter to international business. There is less regulation, more openness to outsiders and a critical mass of skilled people and companies.

Besides, Walsh's claim of a "shrivelling London air network" is simply untrue. Certainly, Heathrow serves fewer destinations - largely because Mr Walsh's own airline has reallocated its Heathrow slots to boost frequency on its most profitable routes.

But London has airports other than Heathrow, whose share of London air traffic is falling. Between them, London's five airports offer direct flights to more international destinations than any other city on Earth, more than they have ever done before. They handle more international passengers than Paris and Frankfurt put together.

Clearly, airport constraints could worsen in future to become more than a marginal factor for the economy. But there is still vast amounts of room at Luton: the fact it's unfashionable isn't a good enough reason for concreting over 10 square miles of west London.

And the main pressure on Heathrow isn't business-related, anyway. The proportion of the airport's passengers travelling on business has actually fallen over the past decade, to just 36 per cent in 2006.

The two biggest single reasons for the packed runways are, firstly, the explosion in leisure trips, particularly by Brits - which take money out of the UK economy, not put it in. This binge flying is unlikely to keep growing as it has done. There are only so many holidays you can have in a year.

The second reason is the rise in Heathrow's transfer business, up 25 per cent in a decade. That has only tangential benefit for London, since transfer passengers never leave the airport. But it has a big benefit for BA.

The reason Willie Walsh rejects expansion at Luton and says "it has to be Heathrow", is that BA wants a proper hub, with vastly more transfer potential, and wants also to cut costs by concentrating its London operation at just one airport.

Those are legitimate objectives but they don't outweigh the health and happiness of two million Londoners, let alone the environmental imperative of preserving the Earth as a "world-class" world. And they certainly shouldn't be dressed up as the be-all and end-all for London's economic future.