New cars and vans powered wholly by gas and diesel will not be sold in the UK from 2030, five years earlier than previously planned, British Prime Minister Boris Johnson said.
But some hybrids would still be allowed, Johnson confirmed.
It is part of what the prime minister calls a "green industrial revolution" to tackle climate change and create jobs in industries such as nuclear power.
Britain had originally planned to ban the sale of new gas and diesel-powered cars from 2040, as part of efforts to reduce greenhouse gas emissions, but in February, Johnson brought this forward to 2035.
An end to the sale of new gas and diesel cars would mark a huge shift in Britain's automotive market.
Industry figures show that gas and diesel-powered cars accounted for 73.6% of new car sales so far this year, while just 5.5% of sales were for pure electric vehicles, which are typically more expensive.
Hybrid vehicles of various types made up the remaining sales.