Net Zero Secretary Ed Miliband slammed protest tactics by Just Stop Oil campaigners as “disastrous” and “alienating” people from the battle against global warming.
The Cabinet minister urged environmentalists instead to help to build a broader coalition to fight climate change.
The Energy Security Secretary declined to be drawn into the case of five Just Stop Oil protestors jailed for up to five years.
But in a more general message, he told ITV’s Good Morning Britain: “I understand the motivation of some of those people of Just Stop Oil, they care about the climate crisis.
“But I think their tactics are disastrous in terms of persuading people to come to our cause.
“Because when you saw what happened in relation to some of those protests, people not being able to go about their business, people not being able to get to see their relatives, and so on, I don’t think that attracted people to the cause that I care about, it actually alienated them.
“So, my appeal to people who are thinking about these issues, who care passionately about these issue, is let’s see how we can build a coalition to support action of the kind that I’m talking about rather than driving people away from it.”
In a letter to Attorney General Richard Hermer KC, the high-profile figures backed millionaire Labour donor Dale Vince and broadcaster Chris Packham’s call for an urgent meeting to discuss “the jailing of truth tellers and their silencing in court”.
It comes after Roger Hallam, 58, was jailed for five years after being found guilty of conspiracy to cause a public nuisance for his involvement in a protest that disrupted the M25 in London for more than four days in 2022.
Cressida Gethin, 22, Daniel Shaw, 38, Lucia Whittaker de Abreu, 35, and Louise Lancaster, 58, were jailed for four years over the demonstration, which saw 45 people climb on to gantries over the motorway.
The jail terms are thought to be the longest sentences ever given for peaceful protest and exceed those handed to two fellow Just Stop Oil protesters for scaling the Queen Elizabeth II Bridge on the Dartford Crossing in October 2022.
Prime Minister Sir Keir Starmer has faced calls to intervene in the case while UN human rights commissioner Volker Turk described the sentences as “deeply troubling”.
Mr Miliband declined to coment on the specific case.
“There has got to be upholding of the rule of law in this country and I as a politician am never going to get into second guessing the decisions the courts make,” he said.
“This is a court case, a judge reached a decision, there may be appeals, so I’m not going to get into that.
“Let me say more generally the right to peaceful protest is an important thing that this Government values, including protests against us, and we have always got to look at the balance - between that right to peaceful protest but also the severe disruption that can be caused to people, the severe damage that can be caused to people’s lives, people going about their everyday business.”
But there was a growing storm over the jail sentences.
Artist Dame Tracey Emin, Coldplay frontman Chris Martin, film director Danny Boyle, author Sir Philip Pullman, singer Annie Lennox and actor Toby Jones were among those who signed the open letter in support of Mr Dale and Mr Packham, who called for the meeting with the Attorney General last week.
Others who put their name down included top human rights lawyer Sir Geoffrey Bindman KC, former Archbishop of Canterbury Rowan Williams and former Labour leader Jeremy Corbyn.
They described the jail terms handed to the activists, known as the Whole Truth Five, as “one of the greatest injustices in a British court in modern history”.
The letter said: “With prisons at breaking point and the new government acting urgently to address this, how can these sentences be seen as anything other than insanity?
“The sentences, ranging from four to five years, are higher than those given to many who commit serious sexual assault.
“The defendants were denied the right to explain to a jury why they took the action they did, making a mockery of the right to a fair trial, with the judge saying that the Crown Prosecution’s agreed facts on climate collapse - including that the world has gone beyond 1.5C for 12 consecutive months - were neither here nor there.”
The signatories argued that the non-violent protesters were “fulfilling a necessary service by alerting the nation to the grave risk we all face, as scientists in their droves express their fear that many of the Earth’s systems are already at breaking point”.
During the trial at Southwark Crown Court, prosecutors alleged the M25 protests led to an economic cost of at least £765,000 while the cost to the Metropolitan Police was more than £1.1 million.
They also allegedly caused more than 50,000 hours of vehicle delay, affecting more than 700,000 vehicles, and left the M25 “compromised” for more than 120 hours.
A spokesperson for the Attorney General’s Office said: “Decisions to prosecute, convict and sentence are, rightly, made independently of Government by the Crown Prosecution Service, juries and judges respectively.
“The Attorney General has no power to intervene in these cases.”
