David Prosser: Heathrow pledge has proved to be an albatross

Outlook Back in the good old days, when David Cameron was only leader of the opposition, there was a great deal of political mileage in making some ground-breaking policy shifts – like ruling out a third runway at Heathrow, for example. In Government, such pledges so often turn out to be more trouble than they are worth.

Yesterday, for example, we heard that ministers will now review airport capacity in the South-east, with the important rider that breaking the Heathrow pledge is not an option.

Now, there are plenty of people who believe we should not pursue any policy of increasing aviation traffic in the skies over London for environmental reasons. That is a coherent argument. It is not coherent, however, to say that you do want to increase capacity, but that you will not do so in the mostaffordable and practical manner.

Does anyone really imagine that asking transit passengers to take a bus or train from Heathrow to Gatwick, say, in order to catch an onward flight will enhance London's reputation as a global aviation hub? Do ministers really think the money can be found, in either the public or the private sector, for Boris Johnson's dream of an airport in the Thames estuary?

The truth is that if you buy theargument that more capacity isrequired – and it is an if – another runway at Heathrow is the best option.