High-speed link a flight of fancy?

In fact, a huge railway station under the airport with fast links to major conurbations might well encourage more people to use Heathrow and attract yet more flights to the hub rather than to regional airports. Given that Lord Adonis seems to accept there is little synergy between the north-south high-speed line and the airport, it is clear the rail announcement was a hastily cobbled-together package designed to appease the environmentalist lobby. This is demonstrated by the sketchy nature of the plans. The projected £20billion cost is merely a guess. There will be enormous wrangles over the route and the environmental impacts. And there are doubts even among supporters about whether routing a high-speed line to Heathrow is sensible.

The commitment to examine its viability is little more than a belated adherence to the Labour Party manifesto, and a response to the Tories, who put Labour on the back foot by supporting the line at their last party conference.

Adonis's launch of the study is nonetheless welcome because the concept needs to be examined, not only from an economic point of view but from an environmental one. It is by no means certain that a high-speed line would be a green project. Quite apart from it requiring enormous resources and energy to build, the line would lead to people travelling longer distances. The Kent high-speed line is encouraging commuters to live farther from London.

Labour should have commissioned such a study years ago, rather than letting the Tories make the running; crucially, it must go into the idea with an open mind. But, as with the third runway, the odds against such a line ever being built remain high.