Supreme Court justices declared that immediate action is needed and have set a deadline for the Government to produce new plans to comply with European Union (EU) law on limits for nitrogen dioxide in the air.
Campaigners want a national network of clean air zones to be in place by 2018 in cities across the UK, but industry experts have warned the government will be left with little choice but to penalise motorists.
There are around 50,000 premature deaths a year from nitrogen dioxide fumes.
Responding to the High Court ruling, a Defra spokeswoman said: "Improving air quality is a priority for this Government and we are determined to cut harmful emissions.
"Our plans have always followed the best available evidence - we have always been clear that we are ready to update them if necessary and have been at the forefront of action in Europe to secure more accurate, real-world emissions testing for diesel cars.”
Experts fear that diesel car drivers will now be forced to pay charges, despite them being ruled out by ministers as they announced five new low emissions zones last December.
In July, Sadiq Khan said that as part of the Clean Air Action plan, drivers of older, less environmentally-friendly cars sold before 2005 would have to pay a £10 pollution charge to enter central London.
The RAC says the Government should instead find ways to encourage motorists to switch to cleaner modern vehicles, rather than punishing existing owners.
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The organisation’s roads policy spokesman Nick Lyes agrees that steps need to be taken to tackle poor air quality, but says many motorists and businesses are worried about being “unfairly targeted” by charges – especially those that switched to diesel cars after they were told it was more environmentally friendly.
He said: “Demonising diesel vehicles as a whole is also extremely short-sighted. Some of the newest diesel vehicles on the road are also some of the cleanest, and diesels will also play a role in helping to reduce CO2 emissions, which contribute to man-made climate change.”