SIR – Yet another potential nightmare for motorists with talk of ‘road pricing’, ie pay-per-mile on motorways or trunk roads.

You don’t have to look far to find the rationale behind this, which has arisen from the Government’s obsession with carbon emissions.

Differential rates of Vehicle Excise Duty (VED) based on the hypothetical amount of carbon produced per mile, regardless of how many actual miles are travelled per year, have forced car manufacturers to design engines using less fuel overall, and also the lowest possible carbon emissions to qualify in some cases for zero VED, or a very low rate.

The combined effect of this has meant less fuel bought, so less Duty and VAT paid, and less income from Vehicle Excise Duty leaving the Treasury short of money, with the only obvious answer to politicians being to invent new ways of fleecing the motorist.

This is nothing new, as years ago VED was based on the theoretical ‘horsepower’ of engines using the RAC formula, which also influenced engine design then.

Surely, it would be far better to have a reasonable standard rate of VED as we had for many years, and also to really crack down on the tax dodgers.

D S Boyes, Rodley Lane, Leeds