New diesel and petrol cars and vans will be banned in the UK from 2040 in a bid to tackle air pollution, the government is set to announce.
Ministers will also unveil a £255m fund to help councils tackle emissions from diesel vehicles, as part of a £3bn package of spending on air quality.
The government will publish its court-mandated clean air strategy later, days before a High Court deadline.
Campaigners said the measures were promising, but more detail was needed.
The government was ordered by the courts to produce new plans to tackle illegal levels of harmful pollutant nitrogen dioxide.
It came after judges agreed with environmental campaigners that previous plans were insufficient to meet EU pollution limits.
Ministers had to set out their draft clean air strategy plans in May, with the final measures due by 31 July.
Local measures could include retrofitting buses and other transport to make them cleaner, changing road layouts, altering features such as speed humps, and re-programming traffic lights to make vehicle-flow smoother.
Campaigners wanted government-funded and mandated clean air zones, with charges for the most-polluting vehicles to enter areas with high pollution, included in the plans, as well as a diesel scrappage scheme.
It is thought ministers will consult on a scrappage scheme later this year, but there is no firm commitment.
Ministers have been wary of being seen to "punish" drivers of diesel cars, who, they argue, bought the vehicles after being encouraged to by the last Labour government because they produced lower carbon emissions.
The UK announcement comes amid signs of an accelerating shift towards electric cars instead of petrol and diesel ones, both at home and abroad:
- Earlier this month, President Emmanuel Macron announced similar plans to phase out diesel and petrol cars in France, also from 2040.
- BMW announced on Tuesday that a fully electric version of the Mini will be built at the Cowley plant in Oxford from 2019.
- Swedish carmaker Volvo has said all new models will have an electric motor from the same year.
"Our plan to deal with dirty diesels will help councils clean up emissions hotspots - often a single road - through common sense measures which do not unfairly penalise ordinary working people."
Environmental law firm ClientEarth welcomed the measures, but said it wanted to see more detail.
Its chief executive James Thornton said: "A clear policy to move people towards cleaner vehicles by banning the sale of petrol and diesel cars and vans after 2040 is welcome, as is more funding for local authorities.
"However, the law says ministers must bring down illegal levels of air pollution as soon as possible, so any measures announced in this plan must be focused on doing that."