It took a matter of minutes in the court of appeal, where demonstrators were strangely absent, for the dial to shift once more on the rights of protest in England and Wales.

The decision taken on Monday by the court of appeal to, in effect, find in favour of the attorney general, the Conservative government’s premier legal officer, has removed a defence for climate protesters that had been available on the statute books since 1971.

Known as the “consent” defence, it allowed defendants on trial for criminal damage to argue that they honestly believed the owner of the property targeted would have consented if they had known of the damage and its circumstances.

In the last year climate protesters successfully used this defence in crown court jury trials. Juries, having heard the evidence, acquitted nine people who targeted the London HQ of HSBC bank, several individuals who daubed paint on the headquarters of the Conservatives, Labour, Liberal Democrats and Greens, and individuals protesting for Palestine Action.

But after the string of not guilty verdicts, Victoria Prentis, the attorney general, stepped in, saying she wanted “clarity on the law as guidance for future cases” involving climate and environmental protesters, as she lodged an appeal on a point of law to the court of appeal.

And on Monday three appeal court judges found in her favour, ruling that the defence, which is contained in the Criminal Damage Act 1971, is inadmissible for those who argue that the facts or effects of the climate crisis are a circumstance that can amount to lawful excuse.

The woman at the centre of the appeal, C, who has spoken to the Guardian, was found not guilty by a jury last year after arguing that the objects of the direct action would have consented if they had known more about the climate emergency.

But the court of appeal judges have now ruled that this will not be available to anyone in future.

The lady chief justice of England and Wales, Sue Carr, said motivations, beliefs, political or philosophical views were too “remote from the damage” to provide a lawful excuse defence.

Climate protesters might point out that the scientific consensus globally on the climate crisis, and the urgency of the need to act, are neither beliefs nor philosophical views, but hard facts. But that held no truck in the court of appeal, where a narrow point of law was analysed in a day-long hearing by bewigged judges, in the absence of any context on the pressing nature of global heating.

The decision removes what is possibly the final defence available to those who take to the streets, daub paint on buildings, or sit peacefully in the road, in an attempt to alert us all to the need for countries to take more urgent action to cut emissions, and limit global heating.

It arguably marks another significant success for political interference with the operation of the law.

It was an earlier intervention by Prentis’s predecessor as attorney general, Suella Braverman, which removed the right to protest under the European convention on human rights, as a defence to criminal damage. Braverman turned to the court of appeal on a point of law after Conservative MPs were angered over the acquittal by a jury of four people for toppling a statue of the slave trader Edward Colston in Bristol.

The planet's most important stories. Get all the week's environment news - the good, the bad and the essential

after newsletter promotion

That decision in 2022 has spun out across courts in England, resulting in judges imposing their own restrictions on scores of defendants, including on those charged not just with criminal damage – which was at the centre of the Braverman challenge – but those charged with less serious public order offences.

At a group of cases at the Inner London crown court, defendants on trial for public nuisance were forbidden from mentioning the words climate change, fuel poverty or referring to the civil rights movement in the US during their trials. Some brave souls refused to comply with what Liberty, the human rights group, said were deeply concerning courtroom restrictions, and were jailed for contempt of court as a result.

Looking on at all of this, Michel Forst, the UN special rapporteur for environmental defenders, has been unequivocal. He warned that the excessive crackdown on climate protesters in England and Wales, involving draconian new laws, excessive restrictions on courtroom evidence and the use of civil injunctions, was having a chilling effect on fundamental freedoms.

Forst spoke before the latest restrictions on what an individual can stand up and say in evidence in a criminal courtroom came through.

It was only in the context of the already highly restrictive rules on the defences available to climate protesters that defendants started to use the consent defence contained in the 1971 act.

And many juries, when they heard the evidence of people such as C, chose to find these men and women not guilty of criminal damage.

But from now on, jurors will no longer be afforded the right to hear a climate protester argue that they had lawful excuse because – in the words of the Independent Panel on Climate Change – rising greenhouse gas emissions are pushing the world to the brink of irrevocable damage and the world is just not acting quickly enough.