The government's plan for tackling the UK's air pollution crisis has been judged illegally poor at the high court, marking the second time in 18 months that ministers have lost in court on the issue.
The defeat is a humiliation for ministers who by law must cut the illegal levels of nitrogen dioxide suffered by dozens of towns and cities in the "shortest possible time".
Legal NGO ClientEarth, which brought the case, argued that current plans ignore many measures that could help achieve this, placing too much weight on costs. On Wednesday Mr Justice Garnham agreed. He also said ministers knew that over-optimistic pollution modelling was being used, based on flawed lab tests of diesel vehicles rather than actual emissions on the road.
But, ClientEarth said that the Air Quality Plan (AQP) which was subsequently produced is "flawed", "woefully inadequate" - and needs to be "drastically" improved. Limits for nitrogen dioxide (N02) were introduced by EU law in 1999, and were to be achieved by 2010.
ClientEarth, which launched legal action in 2011, says that 37 out of 43 zones across the UK "remain in breach of legal limits". During October's hearing in London, ClientEarth argued that unlawful weight was given by the Government to "cost and political sensitivity" when drawing up the new plans.
Nathalie Lieven QC, for ClientEarth, told the judge that the "entire approach" of the Environment Secretary in establishing the 2015 AQP was "driven by cost", and that was "plainly an irrelevant consideration". Dr Penny Woods, chief executive of the British Lung Foundation, said: "We urgently need a new clean air act that restricts the most polluting vehicles from our urban areas and protects everyone's lung health - air pollution affects all of us."
Sam Hall, at conservative thinktank Bright Blue, said there should be more power and funding devolved to local authorities to enable all English cities to set up clean air zones and more support for electric cars.