This target will gradually rise each year before reaching 80pc in 2030, with manufacturers made to pay £15,000 for every petrol car that exceeds their quota – unless they have so-called carbon credits to spend.
But the scheme has prompted stark warnings from bosses at major brands, such as Vauxhall owner Stellantis and Ford, which have said they cannot sacrifice profits by selling EVs at large discounts indefinitely.
Instead, they have previously warned they may be forced to restrict petrol car supplies to artificially boost their ZEV mandate performance.
The warning from Vertu is the first confirmation that carmakers have now begun doing so.
Mr Forrester added that although some people might cheer falling electric car prices, supporters of the ZEV mandate in its current form were “economic buffoons, because car manufacturers are being forced to discount EVs to such an extent that they’re making losses… and that is not a good thing for business”.
He said: “What the Government’s actually doing is constraining the new car market, which has a big impact on VAT receipts for them, and creates a business environment in the UK where manufacturers may question whether they want to make cars here.
“As Carlos Tavares [chief executive of Stellantis] has said, why should they sell cars at a loss because of UK government policy?
“The new car market is no longer a market, unfortunately. It’s a state-imposed supply chain.”
His comments came as Vertu said it expected lower first half profits as demand for new cars and more expensive electric vehicles remained under pressure. The group, which has 192 showrooms and after-sales sites across the UK, said new car sales by volume fell 5.8pc in the five months to July 31.
By contrast, Vertu says there is strong demand for used cars with September expected to be a particularly busy month.
Mr Forrester’s warning comes after the Society for Motor Manufacturers and Traders (SMMT), which represents car makers, slashed its forecast for electric car sales this year amid the ongoing slowdown in demand.
The group now predicts electric vehicles (EVs) will account for 18.5pc of the new car market in 2024, down from an earlier prediction of 19.8pc.
EV registrations surged higher in July but sales to private consumers continued to slump.
Mike Hawes, chief executive of the SMMT, said the weakening demand for EVs among private consumers – despite heavy discounting by car makers – remained the industry’s “overriding concern”.