The British government this week set out a vision for removing the internal combustion engine from Britain's roads by setting a 2040 date for banning the sale of new petrol and diesel cars and vans.

The long-awaited Air Quality Plan features a commitment to end the sale of petrol and diesel cars and vans, alongside wide-ranging plans to increase investment in low emission vehicles and transport infrastructure.

The move, which follows a similar pledge by the French government, is likely to be welcomed by green businesses and campaigners. However, concerns remain about the extent to which the plan will address current fears about the impact of air pollution on urban centers.

Previous versions of the plan, including the latest draft, have been challenged in court with critics alleging that the government's approach fails to meet legal requirements to bring U.K. air quality in line with EU standards as quickly as possible.

Reports this week revealed that the new plan will include $1.31 billion of funding for new ultra-low emission vehicles, $131 million to support electric vehicle (EV) charging infrastructure and grants, and $379 million to retrofit taxis, $1.57 billion to improve walking and cycling infrastructure, and an expanded green bus fund.

It comes just days after the government announced it would invest $322 million in battery R&D and BMW confirmed it would manufacture its new electric Mini at its Oxford factory.

Poor air quality is the biggest environmental risk to public health in the U.K.

The plan is also expected to confirm proposals for a network of Clean Air Zones in many U.K. cities, which will see councils provided with $333 million of funding to take steps to tackle air pollution through a combination of measures, such as changing road layouts and traffic signals and investing in new green buses and taxis.

New plans are expected to be submitted by March and finalized by the end of the year.

The government will argue there is a compelling economic rationale for the new strategy, detailing how poor air quality cost the U.K. up to $3.53 billion in lost productivity in one year.

"Poor air quality is the biggest environmental risk to public health in the U.K. and this government is determined to take strong action in the shortest time possible," a government spokesman said.

"That is why we are providing councils with new funding to accelerate development of local plans, as part of an ambitious [$3.92 billion] program to clean up dirty air around our roads."

However, it remains to be seen if the plan goes far enough to win over campaigners, including the law firm ClientEarth, which has led successful legal action against the government over gaps in previous air quality plans.

Criticism of the draft plan centered on the government's insistence schemes that charge diesel drivers from entering polluted areas would be considered only as a last resort and the failure to commit to a scrappage scheme to encourage people to switch to cleaner vehicles.

The government's own impact assessment revealed that charging schemes, such as the T-charge planned for London by Mayor Sadiq Khan, would have by far the largest and quickest impact on improving air quality.

We cannot wait nearly a quarter of a century for real action to tackle the public health emergency caused by air pollution.

However, speaking to BBC Radio 4 on the new plans, Environment Secretary Michael Gove said charging drivers was a "blunt instrument" that he would prefer to avoid. "Rather than using that blunt instrument I would prefer to use a series of surgical interventions, because I think that is both fairer to drivers but also likely to be more effective more quickly in the areas that count," he said. 

"I don't believe that it is necessary to bring in charging, but we will work with local authorities in order to determine what the best approach is. And if a local authority believes that charging is necessary in order to secure compliance, then we will work to ensure that plan can be implemented appropriately. But on the evidence that I have seen, while charging could bring local authorities into compliance with the law, it's not necessary."

The new plan is expected to include provisions for a narrowly targeted scrappage plan that would help some drivers upgrade, but government sources told the Guardian that while charging schemes remained a possibility all other measures would have to be explored first and there was no plan to force authorities to introduce them.

"Everyone acknowledges that scrappage schemes in the past have been poor value for money," Gove told the BBC. "We know that people are moving away quite rightly from diesel cars at the moment. However, if local authority areas can come up with scrappage schemes that are value for money and are appropriately targeted, then we certainly have no ideological or theological objection to them, and I will work with any particular local authority area that believes that a scrappage scheme would be effective and value for money."  

ClientEarth is likely to study the plan and decide whether further legal action should be pursued.

Areeba Hamid, clean air campaigner at Greenpeace UK, said the 2040 deadline for ending the sale of internal combustion engine vehicles was welcome, but should be brought forward and married with more ambitious short-term action.

Car manufacturers such as Volvo have announced their intention to move away from petrol and diesel by the end of this decade.

"The government is right to put an expiry date on dirty petrol and diesel engines, but 2040 is far too late," she said. "We cannot wait nearly a quarter of a century for real action to tackle the public health emergency caused by air pollution." Car manufacturers such as Volvo have announced their intention to move away from petrol and diesel by the end of this decade. Germany, India, the Netherlands and Norway are considering bans by 2030 or sooner.

"The U.K. has the potential to lead the world in clean transport revolution, but it is vital we stay ahead now through a more ambitious phase-out date to boost our domestic market, as other countries are catching up."

Meanwhile, Khan said without a fully funded diesel scrappage scheme, the air quality plan will "ring hollow."

"The commitment to phase out sales of new diesel cars is welcome, but Londoners suffering right now simply can't afford to wait until 2040," he said in a statement. "We need a fully-funded diesel scrappage fund now to get polluting vehicles off our streets immediately, as well as new powers so that cities across the U.K. can take the action needed to clean up our air.

"Without extra financial support for those who bought polluting vehicles in good faith, then any pledge to clean up our air rings hollow."