Howard Cox at campaign group Fair Fuel argues the idea is good in principle, but “I can’t see it being done fairly”.

“If I drive 15,000 miles per year now, I know the sort of fuel duty I will pay,” he says. “Will I pay the same under the new system? I don’t think anyone in Government is capable of working that out.”

He suggests cyclists should be charged to pay for new lanes, while public transport should get a boost as an alternative. In London the congestion charge is matched with regular buses and trains.

Brian Gregory at the Alliance of British Drivers fears “a huge bureaucratic hierarchy on top of what we are already paying, and the intrusive civil liberties aspect of tracking people everywhere they go.”

Alistair Darling, however, suspects arguments based on privacy may hold less water as time goes on.

“Today more people are aware that if you have a mobile phone in your pocket, someone knows where you are,” the former Chancellor said at a Policy Exchange event.

Offering drivers benefits could help. Edmund King, president of the AA, suggests offering 3,000 “free” miles per year, and to deliberately bring in less money than motorists pay right now.

But he warns the timing is dire for the Government: “Things have transpired against the Government on this because of home energy prices escalating, the cost of living, inflation going up.”

Perhaps not quite the time to bring in a controversial new charge.

Pay-per-mile road charging ‘threatens electric car sales’

The chairman of the influential Transport Select Committee has admitted that his own proposals to charge drivers per mile on the road threaten to slow the switch to electric vehicles.

Huw Merriman is promoting radical plans to move to road pricing to help replace the £35bn drivers pay in vehicle excise and fuel every year.

However, he conceded it would be a “disincentive” to go green before a ban on new petrol and diesel engines in 2030. Hybrids are scheduled to be outlawed in 2035.

Mr Merriman, the Conservative MP for Bexhill and Battle, said: “All road users will need to pay to use the road because otherwise we won’t receive any funds from it, and that will mean electric vehicles.

“But the Department for Transport’s key target is to increase the uptake of electric vehicles, so our report is providing a disincentive to that.”

But speaking at an event organised by the Policy Exchange think tank he insisted that the need to repair the hole in the public finances outweighed the need to promote sales of electric vehicles. In a report this month the Transport Committee urged ministers to act.

Mr Merriman also claimed road pricing would be fair and would encourage people to walk and cycle more, and tackle obesity.

He said: “We can not only ensure that we fund the roads that all motorists need, but also that we reduce congestion, target obesity to get people on active travel more, and I firmly believe that using price as the lever, and choice, is better than just hammering the motorist and telling them what to do.”

For electric car-owners, “I firmly believe motorists are ahead of the game and know ultimately they have to pay when their wheels hit the ground.”

More than 190,000 battery cars were sold in the UK last year, equating to 11.6pc of all sales. That is up from 108,000 in 2020 and 38,000 in 2019, according to the Society of Motor Manufacturers and Traders.