Why was David Cameron so lukewarm in his endorsement of HS2 at PMQs today? (In response to a question about the project’s future, he offered, ‘I believe we should go ahead with HS2′, which is rather than different to asserting that it will go ahead.) The project is – as one Tory minister has told The Spectator – ‘effectively dead’. Ross Clark has investigated why in the cover story of tomorrow’s issue. Here’s what he found:

1). George Osborne has turned against it. The chancellor and Tories’ strategic brain was once HS2’s biggest cheerleader, but experience of office has made him realise that Britain’s limited airport capacity is a bigger threat to economic growth. (Was this behind Cameron’s refusal at PMQs to rule out a U-turn over expansion at Heathrow?)  

2). The replacement of Philip Hammond by Justine Greening as Transport Secretary. Hammond, like his former boss Osborne, was a believer; but Greening was never convinced, and she listens to her parliamentary colleagues’ reservations sympathetically.

3). Cost and commercial sense. There was no mention of a HS2 bill in the Queen’s Speech because the Cabinet Office was sitting on a report that demolished the commercial logic for the scheme, which fuelled arguments for investment in other parts of Britain’s transport infrastructure. A senior Treasury insider tells us that ‘momentum is draining’ in consequence.

4). Weak public support. The lack of enthusiasm for HS2 among those groups it is supposed to impress has damaged the cause. Businesses, councils and people in the Midlands and the North have always been perplexed by the sense of such colossal spending on such a limited project, while the Scots complain that the line would never reach them. Polls have found that only 30 per cent of northern residents believe that HS2 is a good use of public money.

These factors have conspired against HS2 and we are told that it has been kept on ‘life support’ by David Cameron’s backing. Now, even that seems to be tempered. Yet again, an already costly vanity project looks set for the long grass.

UPDATE: The Telegraph’s David Hughes adds some analysis about what this means for Heathrow airport.

UPDATE 2: The Campaign for High Speed Rail has issued a statement saying that our story ‘is deluded…100% Tory party internecine politics.’ To see if they are right, keep a count of the number of ministers enthusing about HS2 over the next few days, or even giving giving off-the-record briefings about how vital it is. As the senior Treasury source told The Spectator, momentum is visibly draining from the project. And in Whitehall, everyone knows it.

Tags: Conservatives, David Cameron, George Osborne, High-speed rail, Justine Greening, Transport