Carmakers sold a record number of electric cars in the UK last year, prompting environmental groups to urge the government to stick to tougher green targets even as the industry argues they are unsustainable.

The number of new cars sold in the UK rose by 2.6% in 2024 to 1.95m, according to the Society of Motor Manufacturers and Traders (SMMT) lobby group. Of those, 19.6% were electric, up from 16.5% a year earlier.

The figures also confirmed the SUV’s rise to dominance in Britain. The “dual purpose” vehicle class, which contains many of the models marketed as sports utility vehicles, outsold other types of car such as the supermini for the first time. SUV sales were helped by the shift to electric, as bulkier cars have more space for a battery.

Electric vehicle (EV) sales have surged over recent years in Britain because of rules forcing manufacturers to sell more every year in an effort to cut the carbon dioxide emissions of transport, which accounted for 28% of all domestic UK carbon pollution in 2022.

The increase in sales has made the UK one of the leaders for electric car adoption around the world, albeit behind Norway and China. However, sales have still been lower than expected, amid an industry-wide slowdown, as well as persistent concerns among some buyers over the higher upfront cost of electric cars and access to public chargers.

The UK government is preparing to relax sales targets for 2025 to avoid imposing steep fines on manufacturers under the country’s zero-emission vehicle (ZEV) mandate. A consultation on changing the rules will close in mid-February.

Carmakers were told to aim for 22% of UK sales to be electric in 2024, rising to 28% in 2025. However, they are able to avoid penalties for missing the main target if they sell more battery cars in later years, or if they cut overall emissions. New AutoMotive, a campaign group, has estimated that the real target may have been as low as 18%.

Nevertheless, the SMMT’s chief executive, Mike Hawes, said there had been a “shortfall” in electric car sales, and that several carmakers had told him privately they might have to buy “credits” from rivals – another way to avoid fines. He said manufacturers were being forced into steep discounts to increase sales of electric cars, a situation that was “unsustainable”.

“The mandate doesn’t move markets,” Hawes said. “The targets have compelled the supply. They don’t compel the demand, and do not by themselves create the market – at least not a healthy one.”

However, environmental campaigners and charge point operators urged the government not to relax the rules. Paul Morozzo, Greenpeace UK’s senior transport campaigner, said record electric sales were an “encouraging indication” Britain was “heading in the right direction” and that the focus now should be on improving access to public chargers and giving more attractive tax incentives on electric cars rather than fossil fuel versions.

The bestselling cars overall during the year were the Ford Puma and the Kia Sportage, both SUVs. The top electric car was the Tesla Model Y, another SUV which was the bestselling model of December as the company raced to push through sales before the end of the year – helping to narrowly retain its position as the world’s biggest seller of EVs.

The share of petrol cars in UK sales fell to 52.2%, while sales of diesels have fallen from 31% of the market in 2018 to only 6.3% in 2024. Sales of hybrids, which combine a petrol engine and a smaller battery, have risen alongside electric cars.

Ben Nelmes, the chief executive of New AutoMotive, said the “UK’s EV transition is pulling into the fast lane”, with nearly one in three cars sold in December being electric.

“Electric car sales have gone up like a rocket in 2024, and December’s figures were well above the target for 2024 and 2025,” he said. “With more cheaper electric models coming to market this trend only looks set to grow, reducing costs for motorists and helping achieve net zero at the same time.”