Sadiq Khan has ruled out scrapping Ulez as the London Mayor eyes a third term in City Hall.
Khan, who expanded the controversial carbon-cutting policy last August, will not change the £12.50 levy.
A spokesperson confirmed the London Mayor will also not increase the charge.
Conservatives and Liberal Democrats in City Hall have voiced concern about the situation.
Sadiq Khan Ulez
PA
Ulez was introduced in 2019 and extended to cover the entirety of Greater London four years later.
The charge, which prompted protests across the capital, applies for vehicles entering the zone in a vehicle that does not meet emission standards.
In a letter to London’s Transport Commissioner Andy Lord, Khan said: “There is clearly still more to do to tackle air pollution, and I'm determined to continue leading from the front in London.
"But my commitment to Londoners is this will not include a new pay-per-mile road user charging scheme or amending the standards for the Ulez scheme.
LATEST DEVELOPMENTS:
Sadiq Khan spoke openly about his plans for Ulez
PA"The introduction and expansion of the Ulez has been necessary and effective. But now it's in place and working, I will ensure the goalposts are not moved for drivers."
A spokesperson added: "For the record, this also means that as long as Sadiq is Mayor the £12.50 Ulez charge will not be increased."
However, the Conservative Party’s City Hall challenger Susan Hall instead promised to scrap the Ulez expansion if she replaces Khan in May.
Hall pledged to instruct TfL to cease enforcement of the carbon-curbing expansion and initiate measures to remove it.
The Ulez was expanded on August 29 PAShe also intends to work with London councils to remove so-called Low Traffic Neighbourhoods.
Launching her bid, Hall said: “Sadiq Khan has ignored Londoners for eight years. If he wins a third term, that would be giving him permission to ignore us again.
“Crime has spiralled out of control after he shut police stations and failed to recruit police, rents have spiked because he has not built the affordable family homes Londoners deserve, and he has imposed his unfair Ulez expansion tax, hitting the lowest earners the hardest.
“I am listening to Londoners. My priorities are Londoners’ priorities and as Mayor, I will recruit more police, build more affordable homes, and scrap the ULEZ expansion on day one.
Susan Hall speaks to protesters at an anti-Ulez demonstrationPA“On May 2, let’s send Sadiq Khan a message and vote for change.”
Liberal Democrat candidate Rob Blackie said: "The Ulez could have been so much more successful if the mayor hadn't rushed the 2023 extension, giving people in outer London just a few months to adapt.
"If we're going to crack climate change we need to bring people with us.
"It's crucial that the mayor focuses on fixing the problems that still persist, especially for tradespeople who need vans for work."