It would be extended to the inner circular route round London for cars, vans, minibuses and motorbikes in 2021, leaving 170,000 motorists facing a choice of paying the levy or switching their vehicle.

Planned Ulez charges for diesel vehicles

Cars: £12.50

Vans: £12.50

Motorbikes: £12.50

Buses: £100

Coaches: £100

HGVs: £100

Mr Khan ruled out a ban on all diesel vehicles, which cities including Paris and Madrid are bringing in, insisting his plans would get rid of more polluting vehicles, sooner.

He said: “The air in London is lethal and I will not stand by and do nothing. Now I urge the Government to step up and match my ambition to transform the appalling air we breathe.

“Ministers need to deliver a national vehicle scrappage fund, reform fiscal incentives like vehicle excise duty and pass a powerful new Clean Air Act to Act end the toxic smog in London once and for all.”

Black cabs will be exempt from the Ulez, while minicabs like Uber will have to pay.

TfL figures show black taxis are currently responsible for 18 per cent of NOx emissions in central London, although all new cabs now have to be zero emissions capable.

Air quality and health campaigners welcomed the announcement while business groups expressed some concerns over the cost to small firms.

Friends of the Earth London campaigner Sophie Neuburg said: “The Mayor is absolutely right to announce plans to reduce the use of diesel in London – and call on Government to take stronger action nationwide.

“His proposals to introduce an Ulez earlier than originally planned, and expand it to the North and South Circular are a good first step. But as things stand, people in inner London will still be breathing in pollution belched out by dirty diesel vehicles for years to come.

“Sadiq Khan must follow the lead of Paris and Madrid, and commit to phase out diesel from London altogether by 2025.”

Dr Penny Woods, chief executive of the British Lung Foundation, said: “It’s great news that the Ulez will be introduced so much earlier than planned. Air pollution is a public health crisis that hits hardest people with a lung condition and children whose lungs are still developing.

However, Colin Stanbridge, chief executive of the London Chamber of Commerce, said: “We agree that it is important to reduce emissions, but we are also concerned about the financial impact on small businesses.

“We have significant concerns about the cost impact on business and would still call for a transitional fund to help those smaller businesses who could possibly go out of business without such support. We would also reiterate calls for an economic assessment by TfL before it goes out to statutory consultation.”