Almost from the moment that the first automobile took to the roads led by a pedestrian waving a red flag, the motorist has been clobbered by the chancellor of the exchequer. The first to seize the opportunity to raise money from the internal combustion engine was David Lloyd George, who in his so-called People’s Budget of 1909 introduced petrol duty, setting the rate at 3d a gallon. That brought the price of a gallon to 1s 1½d, equivalent to about £7 – pretty much where it is now.

Originally, the money was earmarked for a Road Fund but before long it became just another way of raising money for general expenditure. Today, the combined taxes raised from motoring, including vehicle excise duty, are around £45 billion a year; yet only about £12 billion is spent on new roads and maintenance.

The chancellor is always walking on eggshells where any tax is concerned but especially with road charges which have an immediate and regular impact on household finances. For millions who consider driving a necessity, fuel duties (and the VAT on them) make up a tenth of their total non-housing budget.

In 1993, Norman Lamont announced a 10 per cent increase in petrol and diesel duties which he said would in future rise every year by three per cent on average in real terms. The fuel price escalator was born, providing a headache for all his successors in No 11.

Moreover, it was the first time that a tax rise was justified on environmental grounds. Mr Lamont anticipated the additional costs would “provide a strong incentive for motorists to buy more fuel-efficient vehicles”.

Herein lies the contradiction at the heart of excise duties. They raise a lot of money and yet are used to change people’s behaviour in order that they use less of the product that generates the revenue, whether it be tobacco, alcohol or fuel. They cannot in the long run be both a disincentive and a revenue raiser.

In the Commons, Rishi Sunak is expected to cut fuel duties by at least 5 per cent in what would be a complete reversal of the policy announced by his predecessor almost 30 years ago. The fuel price escalator, it is true, has been stopped in its tracks for the past 12 years and was used only fitfully under Labour after protests by lorry drivers at the rising costs threatened to bring the country to a grinding halt.

The political reality is that imposing extra motoring costs is deeply unpopular. Had duties risen as Lamont intended, the Treasury would today be bringing in about £20 billion more a year but successive chancellors have had to forgo the revenue for fear of being sacked or lynched.

If Mr Sunak cuts duties or VAT to ease cost-of-living pressures, he will doubtless be cheered on by those of us currently paying close to £100 to fill the tank, but it hardly fits into the Government’s “green” agenda. Furthermore, there will be a growing group of motorists watching with supreme indifference because they don’t pay these costs.

The owners of electric vehicles escape most of the charges, like Sadiq Khan’s felonious London’s £12.50 Ulez tax imposed on saps like me who bought a diesel car many years ago thinking it would be more efficient and cheaper only to find it turned into Public Enemy No 1. They don’t pay congestion charge either or, obviously, fuel duty.

The big question, therefore, is that as more people switch to electric, where is all the revenue that is currently generated going to come from? There is an answer but it is not one to court popularity and that is road pricing.

It was advocated as long ago as 1964 by the Smeed Committee but not taken up. Labour flirted with the idea briefly 15 years ago after the Eddington Review said the “potential for benefits from a well-designed, large-scale road pricing scheme is unrivalled by any other intervention”. But they backed off after 1.8 million motorists crashed the No 10 website to register their opposition. The Coalition toyed with the proposal as well but shied away.

But on none of those occasions had it been stated as government policy that all petrol and diesel vehicles would be phased out from 2030. To accelerate this process without planning for the revenue consequences is both short-termist and craven since it shoves the responsibility off onto someone else’s shoulders a few years from now.

It was reported yesterday that Downing Street’s policy unit was now looking at plans for a network of toll roads to fill the revenue gap, though a pay-to-drive system looks more probable. The Commons transport committee recently said that road pricing, based on miles travelled and vehicle type, would maintain the existing link between motoring taxation and road usage.

“The Government should act now to replace a potential loss of £35 billion to the Exchequer,” the MPs said, recommending the urgency that has so far been absent.

Taxing electric cars would reduce the incentive to make the switch from petrol and diesel, so road pricing using satellite technology and onboard computers is the only alternative. This would require motorists to install tracking devices so that we pay the right amount depending on where and when we drive.

Supporters say these computers would not be used by government agencies or the police to find out where we have been or how fast we got there. Perish the thought. If you wanted it to work, moreover, you cannot entrust it to the DVLA given its woeful performance over the past two years. And what happens with foreign vehicles – do they pay?

Proponents insist that if road pricing replaces fuel duty and vehicle excise duty it would be revenue neutral, with most motorists paying the same or less than we do now. Somehow I doubt that and try convincing a sceptical public that this would be a benign departure. It will be politically problematic to introduce new charges to shore up revenues when people have bought hybrid or electric cars in the expectation of paying little or no tax on them.

So when Tory MPs cheer Mr Sunak for cutting fuel duty, they need to ask him to explain how the £35 billion annual hole in the budget will be filled in future before the ill-conceived commitment to “net zero” sees the Treasury’s motoring taxes dwindle to, well, zero.