Environmental group ClientEarth has stressed the importance of the EU in providing protection against toxic air pollution, just days before the referendum on Britain's membership.
The group, which includes environmental lawyers, also told Transport Network that Britain would still be subject to EU air quality rules if it was part of the European Economic Area, even after leaving the European Union itself.
A spokesman said that if the UK were to leave the EU, its air quality rules would cease to be part of UK law unless the country chose instead to join the European Economic Area. How quickly the Directive would fall would be a matter of legal argument.
A spokesperson for environment department Defra said it was not able to comment on the issue due to purdah restrictions relating to the referendum.
The comments come after a High Court judge agreed to a request to fast-track ClientEarth's latest court battle with ministers, which will be heard on 18th and 19th October.
ClientEarth lawyer Alan Andrews said: ‘This is good news for everyone who wants to breathe clean air. The Government has been dragging its feet, doing the bare minimum and hoping that air pollution levels drop over time.'
The group is claiming that the Government’s national Air Quality Plan, published last December following an earlier court case, is inadequate and will not bring the UK within the European Air Quality Directive quickly enough in respect of harmful nitrogen dioxide.
Mr Andrews added: 'Unless the Government is forced to act, air pollution will go on making people sick and causing tens of thousands of early deaths every year in this country.
‘The Government has a legal and moral duty to tackle illegal air pollution, for the sake of people who are breathing in toxic fumes day in-day out, as they simply go about their lives.’
He added: ‘This is a reminder of how EU law protects British people from dangerous air pollution.’