London mayor Boris Johnson has provoked a backlash by environmentalists and political opponents by scrapped his predecessor's plans to charge higher polluting cars £25 in congestion fees.
The controversial measure, which delighted environmentalists but outraged some motorists, was due to be introduced October but has now been totally discarded.
Mr Johnson told the BBC: "I am delighted that we have been able to scrap the £25 charge, which would have hit families and small businesses hardest.
"I believe the proposal would actually have made congestion worse by allowing thousands of small cars in for free."
But former mayor Ken Livingstone stood up for his old policy.
"Today's announcement is a further blow to London as a groundbreaking city to tackle climate change and improve the environment," he said.
"The claim that £10 million has been 'saved' by scrapping the CO2 charge is entirely false - in reality London will lose £30-£60 million expected annual revenue from the scheme."
Environmental group Friends of the Earth said the move raised concerns about the new Mayor's green credentials.
The group's London campaigner, Jenny Bates, said: "Boris Johnson is letting the biggest polluters off the hook instead of encouraging people to use cleaner cars.
"In the next few months Boris Johnson and the Conservative party must show they are serious about tackling climate change."
Labour members of the London Assembly pushed Mr Johnson to come up with alternate strategies to combat climate change.
Valerie Shawcross, Labour's transport spokesperson on the London Assembly, said: "These moves may be attractive and financially beneficial to a relatively small number of the most well off Londoners who can afford large vehicles and drive into London regularly. However the long term cost for everyone could prove dire.
"I want to know how the Mayor is actually proposing to help save the planet," she added.
"Mr Johnson has repeatedly stated to the London Assembly that tackling climate change is a 'top priority' but these announcements do not bear this out."
The carmaker Porsche has said its recent legal challenge against the charge has been a success and is expecting legal costs to be rewarded around the six-figure mark.
Managing director Andy Goff said: "We were always confident that our legal case was right and that we would win in the end.
"The charge was clearly unfair and was actually going to increase emissions in London.
"Porsche is proud to have played a decisive role in striking down such a blatantly political tax increase targeting motorists."
The plans would have increased charges on vehicles emitting more than 225 grams of carbon dioxide per kilometre, affecting 17 per cent of those cars entering the congestion zone.