The High Court has told the Government it must publish its plan for improving air quality before the general election.

The Department for Environment, Food and Rural Affairs (Defra) had lodged an application with the High Court late last Friday (April 21) to postpone publication of its draft clean air plan until after the election.  The courts had previously ruled it had to be published by 4pm on Monday, April 24.

Defra had argued publishing it now would breach ‘purdah’ rules limiting Government announcements with political implications during the election period.

However, the High Court decided that purdah was a convention only and did not override legal obligations to clean up the air. Additionally, the impact on public health would exempt it from the purdah rules anyway.

It ordered the draft plans to be published on May 9, five days after the local elections, but before the general election on June 8.

There has been speculation the clean air plan could include potentially controversial measures such as charges for motorists to drive diesel vehicles in towns and cities, or a diesel scrappage scheme.

The court’s decision is the latest development in a long-running legal action brought against the Government by a group of environmental lawyers, ClientEarth. The campaigners began proceedings after the UK breached EU limits for nitrogen dioxide (NO2) in the air.

ClientEarth CEO James Thornton, said: “We are delighted with the ruling. We cannot afford more dither and delay from the government. Rather than appeal this decision, they need to get on and produce their plans to bring down air pollution as soon as possible.

“The judge agreed with us that this is a matter of public health, not politics.”

The Government is expected to appeal the court ruling, which could yet mean it succeeds in delaying the publication of its air quality plan until after the general election.