New diesel and petrol cars and vans will be banned from 2040 as part of efforts to tackle air pollution, the Government is expected to announce.
A £255m fund is expected to be unveiled to help councils speed up local measures to deal with pollution from diesel vehicles, as part of £3bn in spending on air quality.
Yet critics said the 2040 ban was "too little too late", with the Liberal Democrats calling for new diesel sales to end by 2025.
Meanwhile former Labour leader and Energy Secretary Ed Miliband said the move was a "smokescreen" hiding a lack of immediate action to reduce emissions.
The Government is set to include the 2040 ban in a court-mandated clean air strategy due to be published on Wednesday, just days before the deadline set by the High Court.
The expected move to ban petrol and diesel vans and cars follows similar plans announced in France this month and amid increasing signs that the shift to electric vehicles is accelerating.
On Tuesday, BMW announced plans for an electric Mini to be assembled at its Oxford plant while earlier this month Volvo unveiled its moves towards cleaner cars.
The Government was ordered to produce new plans to tackle illegal levels of harmful pollutant nitrogen dioxide after the courts agreed with environmental campaigners that a previous set of plans were insufficient to meet EU pollution limits.
Despite government efforts to delay publication of the plans until after the general election, ministers were forced to set out the draft plans in May, with the final measures due by July 31.
It is thought ministers will also consult on a diesel scrappage scheme to take the dirtiest vehicles off the road.
Green Party co-leader Caroline Lucas said the scrappage scheme was needed immediately to reduce emissions.
Campaigners have demanded the final plans should include government-funded and mandated clean air zones, with charges for the most polluting vehicles to enter areas with high air pollution, as well as a diesel scrappage scheme.
Their calls for charging zones were backed up by an assessment published alongside the draft plans which suggested they were the most effective measures to tackle nitrogen dioxide, much of which comes from diesel vehicles.
But ministers have been wary of being seen to "punish" drivers of diesel cars, who they claim bought the vehicles in good faith after being encouraged to by the last Labour government on the basis they produced lower carbon emissions.
They favour local measures such as retrofitting buses and other transport to make them cleaner, changing road layouts and even altering features such as speed humps and re-programming traffic lights to make traffic flow more smoothly to reduce pollution.
The expected move to ban diesel and petrol cars and vans by 2040 comes after similar plans were announced in France this month and amid increasing signs that the shift to electric vehicles is accelerating, with BMW announcing plans for an electric Mini and Volvo unveiling its moves towards cleaner cars.
Air pollution is linked to around 40,000 premature deaths a year in the UK, and transport also makes up a significant share of greenhouse gas emissions.
A Government spokesman said: "Poor air quality is the biggest environmental risk to public health in the UK and this government is determined to take strong action in the shortest time possible.
"That is why we are providing councils with new funding to accelerate development of local plans, as part of an ambitious £3bn programme to clean up dirty air around our roads.
"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.
"Diesel drivers are not to blame and, to help them switch to cleaner vehicles, the Government will consult on a targeted scrappage scheme, one of a number of measures to support motorists affected by local plans."
Liberal Democrat transport spokeswoman Jenny Randerson said: "By scrapping the scrappage scheme the government have U-turned on their offer a life line to the millions of owners of diesel cars up and down the country. This is a betrayal to drivers everywhere.
"Air pollution is poisoning our children and leading to causing avoidable deaths across the country.
"Instead of properly fighting this silent killer the government has flip-flopped, offering tax breaks for cars that they are now banning. The Government's feeble attempts to tackle air pollution are too little too late.
"The Government needs to take drastic action to end this public health crisis, every moment they sit on their hands more people are breathing in and dying from polluted air.
"The Liberal Democrats have called for all new diesel sales to end by 2025 and a scrappage scheme to help drivers convert to greener vehicles. We are serious about fighting air pollution, this Government is not."
Additional reporting by agencies
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