Tony Blair has good reason to worry about the price of petrol. The fuel tax protest that caught his Government unawares five years ago was a sharp reminder that the motoring lobby is large, vociferous and acutely sensitive to what it sees as gouging by government or international oil companies. Motorists are equally incensed by the high cost of road tax, especially as they know that most of the revenue is not spent on roads or even on transport infrastructure, but is an important component of general taxation. Any scheme that proposes to abolish both these unpopular charges ought, therefore, to command immediate support in Whitehall. Those who think that gravely underestimate Treasury conservatism and ministerial caution.

It is almost a year since this newspaper carried a headline almost identical to those publications that yesterday reported Alistair Darling’s call for a road-pricing scheme to replace fuel duty and road tax. The Transport Secretary again rehearsed arguments that were well aired last year, and indeed have been around for far longer. Using satellite technology to keep track of cars and to charge motorists according to where, when and how often they drive was, Mr Darling said, fairer, more environmentally friendly and the only way to prevent gridlock on the roads at peak times.

He is right. As London’s congestion charge has begun to show, it is technologically feasible and politically possible to log individual journeys and charge motorists if they drive at peak periods or in designated zones. A more sophisticated nationwide scheme would allow ministers to set higher rates in rush hours or on crowded roads while also keeping them much lower in rural areas. This would not only deter motorists on roads already unable to bear more traffic, but it would also benefit the rural poor who are often forced to drive long distances because of a lack of public transport. Road pricing is also fairer. For whereas mileage is mostly marginal to those who have already paid the annual road tax, a charge based on the distance driven will cost less for people owning a car but using it infrequently.

Mr Darling, however, seems to lack the courage of his convictions. He warns the public not to “dance around this for years” but is performing the very same jig himself. He argues that it will take ten years to carry out feasibility studies and win public acceptance, and at least six years before even launching a pilot scheme in Manchester or the West Midlands.

Congestion, meanwhile, will worsen, petrol prices may well rise and viable alternatives are still in the distance. Pessimists believe that little can be done and that Britain must simply accept less mobility for future generations. Rod Eddington, the chief executive of British Airways, who has been commissioned by the Government to investigate transport needs, believes this to be profoundly mistaken. Mobility, he rightly believes, not only promotes trade, broadens horizons and encourages social cohesion; it can help to dispel ignorance, counter prejudice and even encourage international understanding. Mobility demands investment, however. And Mr Eddington believes that huge sums will be needed to improve ports and airports, underpin public transport and unclog Britain’s sclerotic road and rail systems. Road pricing would be a start. Mr Darling should end his minuet and lay out concrete proposals forthwith.