ENVIRONMENTALISTS have branded the UK Government’s plans to clean up Scotland’s air “inadequate” as they prepare to take it to the High Court in London this week.

ClientEarth, a group of campaigning lawyers, believes Whitehall’s failure to come up with specific measures for devolved nations, including Wales and Northern Ireland, is unlawful.

The group has already used the London court to force ministers to produce a draft plan to clear air, described by Friends of the Earth as being so dirty it amounted to a public health crisis.

Glasgow has been branded the “the most polluted city in Scotland” due to what the lawyers from ClientEarth call “illegal and harmful levels” of nitrogen dioxide (NO2), which comes mostly from diesel vehicles.

Now they say the plan failed to address specific issues outside England and is “fundamentally flawed” inside the UK’s biggest constituent nation.

Chief executive James Thornton said: “The draft plans for Scotland, Wales and Northern Ireland are simply plans for more plans.

“The court ordered a plan for the UK Government to obey the law on pollution limits across the UK as soon as possible. The health of all UK citizens is at stake, not just some.”

ClientEarth is taking the Secretary of State for the Environment Food and Rural Affairs (Defra), currently Michael Gove, to the High Court for failing to comply with the court’s order to produce a plan to bring air pollution across the UK within legal levels as soon as possible.

The court will hear the campaign group’s challenge on Wednesday.

The UK was found to be in breach of EU air quality standards earlier this year with the European Commission issuing a final warning in February. Some of the worst pollution hotspots in Britain are north of the Border.

Last year, Government monitoring found dangerous levels of NO2 and tiny sooty particles are polluting busy streets across Scotland, which are estimated to lead to some 2,000 early deaths each year north of the Border.

Hope Street in Glasgow was named the worst ranked street in the country for the life endangering substances, with St John’s Road, Edinburgh, second.

Similar high emissions are to be found in streets in Aberdeen, Dundee, Falkirk, Perth, Crieff and Cambuslang, South Lanarkshire.

Friends of the Earth said Scotland was in the midst of a “air pollution health crisis”. Britain, once dubbed the “dirty man of Europe” was supposed to meet EU standards by 2010.

The most polluted street in Scotland was St John’s Road in Edinburgh, which was 60 per cent over the legal limit, followed by Hope Street in Glasgow. Diesel cars, lorries and buses cause most of the pollution.

ClientEarth in April forced Defra to publish a plan in April after the High Court accepted arguments the matter was not in purdah because of the then ongoing General Election. The body said it had tried to avoid further legal action by writing to ministers. Defra has argued it consulted “for the entire UK”. As the member state it is responsible for meeting EU directives through air quality but actual implementation is a matter for the Scottish Government.

A Defra spokesman said: “Improving the UK’s air quality and cutting harmful emissions is a priority for this Government. We have invested more than £2 billion since 2011 to increase the uptake of ultra-low emissions vehicles and support greener transport schemes, and set out how we will improve air quality through a new programme of Clean Air Zones.”

A Scottish Government spokesman said it had made “strong progress” in reducing air pollution levels and would “continue to build on these achievements”.

He added: “We have already sought to shape the UK Government’s plan with our Clearer Air for Scotland Strategy, which sets out ambitious actions designed to secure further improvements in Scotland’s air quality.”

As part of The Herald’s landmark Beyond Brexit series it emerged a raft of EU regulations that would be at risk include directives on air quality, water framework, bathing water, habitats, wild birds, wild flora and fauna, environmental impact and renewable energy and regulations covering pesticides and packaging waste.

A report by academics of the Scottish Universities Legal Network on Europe recently warned one of the main risks arising from Brexit... was “losing the ‘hard, enforceable edge’ that EU law provides to the Aarhus Convention’s provisions...”

Environmentalists warn only restrictions on diesel and other vehicles entering Scottish cities would make air fit to breathe. Councils have yet to use their power to do this.

It is believed some 40,000 early deaths are caused across the UK by emissions.