The government has confirmed the majority of new cars sold in Britain will have to be electric by 2030 despite Rishi Sunak’s decision last week to delay a ban on petrol and diesel cars by five years.

Under the long-awaited zero emissions vehicle (ZEV) mandate, 80% of sales must be fully electric, or another alternative, within seven years. Carmakers would have to pay £15,000 for each petrol or diesel engine above that threshold, the Department for Transport said on Thursday.

The announcement broadly confirms proposals in March, modelled on moves in California, which will force manufacturers to rapidly increase the proportion of battery electric carsproduced.

It was greeted with relief from environmental campaigners, who had feared the government would further water down its green commitments after the U-turn on the 2030 ban on all petrol and diesel sales.

However, the government did soften the mandate slightly for vans, where the transition to electric has been slower than for cars.

Richard Hebditch, the UK director of the thinktank Transport & Environment, said for all the fanfare of the U-turn on the government’s 2030 ban on internal combustion engines, “the zero emissions vehicle mandate will pretty much end sales of new petrol and diesel cars by the early 2030s.

“Last week’s announcement pushing back the phase-out dates for new petrol and diesel cars could have blown a huge hole in our carbon budgets. But its impact is now set to be limited by a mandate that squeezes sales every year.”

Under the plans, 22% of sales in 2024 must be powered by batteries, compared with the actual figure of 20.1% in August this year. The proportion will rise annually, hitting 52% in 2028, two-thirds in 2029, and 80% in 2030. Alternatives such as hydrogen fuel cells will also count but in practice there is almost no market for them and batteries are set to dominate.

Lisa Brankin, the UK chair of Ford, said the US carmaker’s plans to go all-electric in Europe by 2030 were “unwavering” after she criticised the UK’s U-turn on the 2030 ban. She welcomed the ZEV mandate because it would provide “a strong investment signal to infrastructure providers to accelerate installation of new charge points”.

A lack of public chargers is seen as one of the key factors slowing the transition to electric cars.