The 1.8 million signatures on the recent road pricing petition is the least of the problems facing supporters of the concept. The plan to introduce a workable pay-as-you-drive scheme is pitted with so many potholes that it is difficult to see how politicians will ever manage to drive it through and implement anything like a comprehensive national system.
And I say "a" rather than "the" system, because there is no model, let alone a detailed scheme for it. That besides, the petition was a thoroughly dishonest exercise and was based on an email campaign which suggested that a very precise plan set a tariff of £1.30 per mile, with the additional cost of the "tag" - the GPS equipment on board that calculates the distance travelled - to be £200.
The ideas for road pricing that have been floated are various, but we are years away from any decision on charging rates or how the tags would be paid for. Given that no scheme exists, the petition was really an exercise in enlisting people who are against paying a supposedly new tax - and a man with more courage than Tony Blair would have said so.
There is no worked-out model because a national system would look very different from the only large-scale scheme currently in operation: London's congestion charge. London is exceptional for many reasons, not least the excellence of its public transport, with 12 Tube lines and 700 bus routes and a low rate of car usage. Since it came into operation in 2003 the initial congestion charge has, indeed, been a success in reducing traffic by 20 per cent, even though, at a cost of £161.7m, it has been expensive to introduce.
The western extension, controversially introduced last month to double the congestion charge's catchment area, has shakier foundations and may prove damaging to perceptions of the scheme's success.
It takes in an area that is largely residential - few people travel to work there - and the decision to allow residents a 90 per cent discount to drive in the whole area gave the affluent residents of Westminster, Kensington and Chelsea leave to enter the original charging area for less than they were paying before. That the good burghers of Kensington held protests at their town hall suggests the relationship between brains and wealth is as tenuous as ever, even in these meritocratic times - a case of turkeys failing to support the abolition of Christmas.
The most telling phrase in Tony Blair's answer to the online petitioners was that "it would be ten years or more before any national scheme was technologically, never mind politically, feasible". 'Twas ever thus. Road pricing has always been ten years off. In 1993 the then transport secretary, John MacGregor, voiced commitment to introduce a scheme within a decade. Labour ministers have been saying the same thing for the past few years, seemingly unaware of the passage of time.
Blair is technologically illiterate and his response is dishonest. The technology to introduce a national scheme is available and already being used in Germany, where all lorries are charged to use the motorways. Nine out of ten pay through a sophisticated tagging system with an on-board unit that uses the US satellite system Toll Collect to calculate distance travelled. Operated by T-Systems, a subsidiary of T-Mobile, Toll Collect is 99 per cent accurate, and has been shown to function properly even in urban areas where there were concerns that tall buildings would cause black spots.
In Britain, a similar system was planned to assuage complaints by the road haulage industry that foreign lorries were getting a free ride on our motorways. However, in 2005, Alistair Darling, the then transport secretary, abruptly cancelled the proposed lorry road charging scheme, arguing that it would get in the way of the national scheme being proposed for all motorists - which, of course, he said would be ten years down the line.
This explanation does not hold water. The lorry scheme would have been an incredibly useful trial run for the wider implementation of the system. Instead it revealed political cowardice from a minister who had been sent to the Department for Transport to keep the ministry out of the headlines following the negative coverage that his immediate pre decessor, Stephen Byers, had managed to produce.
Despite making the scheme acceptable to hauliers by promising it would replace existing forms of taxation, and therefore be revenue-neutral, Darling was simply too scared of potential resistance from hauliers, a group that has terrified government ministers since the fuel protests of 2000, which almost brought the country to a standstill. This was a lost opportunity to soften up public opinion and sort out the technology.
This episode demonstrates that the biggest obstacle in implementing a national road pri-cing scheme is political, not technical. And it leads to the crucial question: What would be the purpose of a national road charging scheme? For a while ministers, ever fearful of the Jeremy Clarkson brigade, seemed to imply that it would be revenue-neutral, simply replacing fuel tax and vehicle excise duty.
That did not make sense at the time and makes even less now. The enormous costs and the political capital needed to introduce a national road pricing scheme would be disproportionate if its aim were simply to reduce congestion a tad on a few overcrowded roads. The sole rationale for imposing such an expensive and far-reaching measure would be to reduce the environmental damage caused by cars and induce a shift to other, greener, forms of transport.
Lack of political will
Here, however, there appears to be further trouble ahead as the incoherence of wider government transport policy is horribly exposed. At present, rail fares are being allowed to rise by 1 per cent above inflation. For the buses, too, fare increases above inflation in the deregulated and privatised sector are the norm. But Britain has in the past invested far less of its GDP in transport infrastructure than other comparable European economies - with the result that people induced out of their cars by the stick of heavy taxation have few carrots of nice, shiny trains or fleets of state-of-the-art buses with which to console themselves.
Aware of this, ministers tried to offload the political risk of implementing the scheme on to local authorities, offering generous bribes in the form of a Transport Infrastructure Fund that comes in two parts: the first to fund feasibility studies and the second for the implementation of schemes. Local authorities in large conurbations such as Manchester and Birmingham came back saying: "Give us lots of money to pay for better public transport, and then we will im plement road pricing." Even those areas which have been allocated money for feasibility studies, such as Norfolk, are worried about actually spending the money because of fears of a hostile local response.
Given such a reaction on the ground, and the ease with which motorists' fear of extra taxation can be roused by public campaigns, road pricing in Britain is likely to be mired in endless discussion, documents and feasibility studies for far longer than a decade.
A national scheme would require great courage and conviction, and there are few signs of either from the Department for Transport. Without that, and, more importantly, without strong political leadership, a scheme that could reduce congestion and reduce carbon emissions will forever remain "ten years away".
Christian Wolmar's book on the history of the railways, "Fire and Steam", will be published by Atlantic Books in September (priced £19.99)
Road pricing facts and figures
1.8 million people signed e-petition against road pricing
33 million cars currently on UK roads
25% increase in congestion predicted by 2015
£22bn value of time wasted in England due to congestion by 2025
£62bn set-up cost of road pricing scheme
£8bn to administer scheme every year
£1.50 per mile toll planned for busiest roads during rush hour
21% of UK carbon emissions come from road traffic
£140bn investment on public transport by 2015
£28bn annual benefit to the UK economy
Research by Mosarrof Hussain