The Aarhus Convention is an international treaty, signed by the UK, to guarantee the public access to information, participation in decision-making, and the ability to contest green controversies in law.
But the UN Economic and Social Council has judged that the government has failed to act on previous warnings that it is “prohibitively expensive” for campaigners to bring legal action over environmental issues.
While progress has been made in some areas, the UK has not “met the requirements” set down as far back as 2017, its ruling said.
Ministers have been told to “ensure that the allocation of costs in all court procedures ... is fair and equitable and not prohibitively expensive”.
They must also consider “assistance mechanisms to remove or reduce financial barriers to access to justice” and are required to submit an action plan by no later than next July.
The judgment is a further embarrassment for the government ahead of the landmark Cop26 summit in Glasgow, following controversies over delays to passing its Environment Bill.
The group ClientEarth, which has pursued No 10 over the convention – drawn up 20 years ago – said the government was “not serious about holding itself to a high standard”.
“Amid the current climate and biodiversity crises, it is more important than ever for the public to be able to exercise their environmental rights,” said Gillian Lobo, a senior lawyer, “whether that be requesting information from the government or challenging them in court when they make unlawful decisions.
“The UK should be taking all necessary steps to comply with the treaty it has ratified on access to justice, not making its position worse.”
Ms Lobo warned that government threats to curb the use of judicial review threatened to “shift the dial further in the wrong direction”.
There are 47 parties to the Aarhus Convention – 46 nations in Europe and central Asia, plus the European Union – and it is legally binding for those who have signed it.
It is designed to build trust between members of the public and governments by demonstrating that people’s participation in the decision-making process is valued.
Four years ago, in 2017, the UK was told to submit a detailed progress report after the compliance committee said that recent policies were moving the UK further away from the convention’s goals.
That progress report, submitted in 2018 – plus later ones in 2019 and in October last year – have now also been rejected by the committee, but there is no mechanism to compel the UK to comply.
A Department for Environment, Food and Rural Affairs spokesperson said: “The UK takes its Aarhus obligations seriously and we are disappointed with a number of the compliance findings.
“We will continue to work closely with the UN to enhance global environmental governance standards.”