Leading article: Too easily seduced by the glamour of high-speed rail

In a climate of economic austerity and seemingly endless spending cuts, plans to build a high-speed rail link between London and Birmingham look more attractive than ever.

Trains speeding along at up to 250mph, travel time cut from nearly an hour and a half to a nippy 49 minutes, £17bn-worth of stimulatory infrastructure investment. Between the undeniable glamour of futuristic technology and proponents' sweeping claims about job creation, economic growth and international competitiveness, the High Speed 2 (HS2) project looks like just the tonic Britain needs. The only problem is that the numbers simply do not add up.

Worryingly, the decision to go ahead with HS2 appears all but made. Ahead of the formal announcement expected from Justine Greening, the Transport Secretary, next week, an array of economists, business people and trade unions stepped forward yesterday to put the case for the first phase of a £32bn scheme that will ultimately extend in a "Y" to Man-chester and Leeds. They cited optimistic predictions of a million new jobs (including thousands in construction and engineering) and bewailed the international "embarrassment" of Britain's lack of a high-speed link with the North. And in response, Ms Greening published supportive research from Network Rail, giving the clearest indication yet that the Government is of a similar mind.

In fairness to Ms Greening, it is a difficult call. All three of the main political parties are ostensibly in favour of HS2. And the loudest complaints have come from Chilterns residents – often Tories – concerned about their backyards, leaving the Secretary of State open to charges of narrow self-interest if she opposes the scheme. She should still be doing so.

Never mind the Nimby arguments. They may have captured the most air time, but such concerns would be nothing were the case in favour of development sufficiently strong. It is here that the fantasy starts to give way to reality.

At the broadest level, the connection between transport networks and economic growth is undeniably well proven. Indeed, this newspaper supported the HS2 scheme at its inception on just such grounds. But the assumption was that the gaps in the business case would be satisfactorily filled. Despite all the consultations, reviews and analyses in the intervening years, they have not.

Rather, the £22bn-worth of benefits HS2 is expected to foster are based on calculations that are, at best, rather vague. Some £11bn of them are predicated on time savings for business people, which are arbitrary in their valuation and assume travel time to be economically valueless despite laptops and mobile phones. The claim of several billion pounds more to be reaped from economic stimulation outside the South-east is equally suspect and there are strong arguments that faster links to London merely entrench the capital's dominance and widen the North-South divide still further.

The most convincing argument in favour of HS2 is that it will act as a much-needed bypass, easing the congestion that bedevils the West Coast Main Line. But to plump for an all-new high-speed rail link, rather than dealing with the bottlenecks in the existing network, runs counter to the advice of the most recent review of Britain's transport infrastructure and relies on passenger numbers soaring at an unprecedented rate to balance the sums.

That Britain's moribund economy would reap a positive Keynsian boost from a slug of capital investment by Government is no excuse to be indiscriminate. There is no shortage of transport schemes – both rail and road – which would more reliably create jobs and boost growth. The vast investment in HS2 would be more effectively spent elsewhere.