A TALENTED musician who halted her Cambridge University course to take up climate activism has been jailed for four years for plotting to bring the M25 to a halt.

Former Hereford Cathedral School pupil Cressida Gethin, 22 – who comes from Dorstone just over the Wales-England border in Herefordshire – appeared in court alongside four other co-founders of the controversial Just Stop Oil group, who were jailed for a total of 21 years after a judge said they had "crossed the line from concerned campaigner to fanatic".

TV wildlife presenter Chris Packham and Green Party-supporting celebrity chef Hugh Fearnley-Whittingstall were among those who condemned the sentences of the self-styled ‘Whole Truth Five’, who were locked up at Southwark Crown Court under tough new laws.

But other commentators said it was about time activists paid the price for direct action protests that inconvenienced hundreds and thousands.

Forty five Just Stop Oil protestors climbed gantries on the M25 in November 2022 to protest the UK reaching record temperatures of 40C, forcing police to close the road to traffic and causing gridlock in and around London over four days, extending to closures on connecting motorways.

People missed flights, medical appointments and exams, while two lorries collided and a police motorcyclist came off his bike when trying to bring traffic to a halt in a “rolling road block”, the court heard.

Prosecutors said that the protests, jointly organised by South Wales smallholder and Extinction Rebellion founder Roger Hallam, had caused an economic cost of at least £765,000, while the Metropolitan Police bill was more than £1.1m.

The sentences are the longest since the last government introduced a new law of conspiracy to cause a public nuisance, targeted at clamping down on disruptive protests. The five defendants denied the charge, but were convicted after a trial.

Police were made aware of the conspiracy after a journalist infiltrated a zoom call, showing the "intricate planning and level of sophistication involved".

Gethin, who spent 27 days on remand over another road protest last year before the charges were dropped, was arrested close to the M25 dressed to climb the gantries that cross the motorway.

She told Judge Christopher Hehir: "It was always my intention to limit the harm caused by the disruption."

But she added that it would not have happened if "those in power had been taking their responsibilities seriously".

“​I want to remind the court once more that my reasons for taking action were not beliefs or opinions," she added.

"Earth’s life-support systems are breaking down due to human activities, whether we believe it or not.

"These are not beliefs or opinions and feeling strongly that this is wrong is greatly understandable, I would argue. I deeply regret that this action was necessary – I maintain that it was necessary and I stand by my actions as the most effective option available to me.”

In April, Gethin told student newspaper Varsity that Cambridge University gave legitimacy to companies that “kill people around the world” through its fossil fuel partnerships.

During the hearings, 11 protestors carrying placards saying: "Jurors have an absolute right to acquit a defendant according to their conscience," were arrested for contempt of court, which was later dropped, with the judge saying Hallam had "orchestrated" the protest, although they denied he had been involved after the hearing.

Hallam, 58, claimed during the trial: “The corruption of our judges by the carbon state has crossed a line in the sand.

“This is an opportunity, and an obligation, to act. We only have a limited amount of time to halt the unimaginable horrors of climate and social collapse - and to save our democracy.”

Jailing Hallam for five years and the others for four, Judge Hehir said: “The plain fact is that each of you some time ago has crossed the line from concerned campaigner to fanatic.

"You have appointed yourselves as sole arbiters of what should be done about climate change.”

Following the sentencing, Gethin’s parents – former London Symphony Orchestra cellist Nick Gethin and fellow classical musician Cathy Nelson – both said they are standing by her.

Despite being held up by the M25 protest for more than four hours, TV presenter and conservationist Chris Packham slammed what he called the "reckless and irresponsible erosion of our human rights" after the sentencing.

He claimed that "five peaceful protesters had been denied the right to properly assert what motivated their alleged crimes", while jurors had been "robbed of their fundamental right to acquit defendants on the basis of their conscience".

Speaking outside the court, he added: "I stand here because I believe this represents the direct theft of our freedom, the destruction of our democracy, the deliberate and calculated intimidation of protesters, and that unless we resist this, the very real danger is that our species will destroy life on Earth."

River Cottage star Hugh Fearnley-Whittingstall said: "Today five people who care about our planet have been viciously sentenced under laws that remove our right to peaceful protest.

"So I came to join those who stand in solidarity. We cannot put people behind bars for urging us to do what we know is right."