The number of petrol cars on British roads has peaked this year but is set to tumble by more than 40% over the next decade, according to a report.

Auto Trader’s latest motoring forecast estimates there were 18.7m petrol-powered cars on the roads this year, but that this will steadily decrease from 2025 to 11.1m by 2034.

The online vehicle platform expects a “seismic shift” towards electric vehicles (EV) in the next 10 years as affordability improves, from 1.25m in 2024 to 13.7m. The EV share of the new car market will rise from about 18% to 23% in 2025, according to Auto Trader.

This is still far below the 28% target for sales under the UK government’s Zero Emissions Vehicle (ZEV) mandate. Under the current rules, this requires 22% of all new car sales to be battery-electric vehicles in 2024, with the target rising each year to 80% by 2030 and 100% in 2035.

Carmakers and retailers have expressed fears the mandate is putting jobs at risk at UK vehicle factories and piling pressure on manufacturers, with demand for EVs flagging due to their high costs.

Concerns have also been raised over a lack of charging infrastructure across the country to support the transition to electric vehicles.

Last week, Vauxhall owner Stellantis announced the closure of its van-making factory in Luton, putting 1,100 jobs at risk, and said the decision was made within the context of the “stringent” UK zero-emission vehicle mandate.

Ian Plummer, the commercial director at Auto Trader, said: “Peak petrol is a genuine landmark for the UK. We expect to see a seismic shift in British motoring over the next decade as the number of petrol cars falls by nearly half and EVs take a much bigger share.

“All this is happening against the backdrop of exceptionally strong used car demand despite a range of challenges for the industry, not least the introduction of ZEV targets, constrained supply, changing finance rules, and the budget.”

The group said demand for used cars continued to remain resilient and was set to edge up from 7.61m sales this year to 7.7m in 2025, with secondhand EVs becoming more popular as prices pare back.

Its data shows the gap between EV and petrol or diesel vehicles is closing, with one in three used EVs on its platform priced under £20,000.

A growing number of three- to five-year-old EVs cost the same or less than their petrol or diesel counterparts, it added.

Motorist demand for new cars has been flagging in recent years amid cost of living pressures, with Auto Trader predicting sales would edge up by 2% next year to 1.98m, still leaving it 14% below the 2.31m peak for registrations before the pandemic struck in 2019.