Five Just Stop Oil protesters have been jailed for several years for conspiring to organise protests that blocked the M25 motorway.

Roger Hallam, 58, Daniel Shaw, 38, Louise Lancaster, 58, Lucia Whittaker De Abreu, 35, and Cressida Gethin, 22, agreed to cause disruption to traffic by having protesters climb onto gantries over the motorway for four successive days in November 2022.

Hallam, co-founder of Just Stop Oil and Extinction Rebellion, was sentenced to five years imprisonment while the remaining four defendants were each handed four years’ imprisonment in what are thought to be the longest sentences ever given for peaceful protest.

The sentences exceed those handed to fellow Just Stop Oil protesters Morgan Trowland and Marcus Decker, who scaled the Queen Elizabeth II Bridge on the Dartford Crossing in October 2022.

The Court of Appeal was later told Trowland, who was given a three-year sentence, and Decker, who was jailed for two years and seven months, were given the longest terms given for a peaceful protest case in modern times.

Speaking at a press conference after the sentencing outside Southwark Crown Court on Thursday, TV presenter Packham said: “Be clear, be very, very clear, this is not just about climate activism.

“The laws that have been drafted, the injustices that are being wrought, threaten all rights of free speech.

“We stand here today because our future security may be comprised by the reckless and irresponsible erosion of our human rights, of our fundamental freedoms.”

“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 our protesters, and that, unless we resist this, the very real danger is that our species will destroy life on Earth.”

Packham called for a recorded meeting with new Attorney General Richard Hermer “as rapidly as possible” so that he could “address this grotesque miscarriage of justice”.

Chef Hugh Fearnley-Whittingstall, also speaking at the press conference, said the protesters had been “really viciously sentenced under some extraordinary, wicked, malicious legislation”, and the laws had been put in place to “protect a version of business-as-usual”.

Prosecutors alleged the M25 protests, which saw 45 people climb up the gantries, 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 police officer suffered concussion and bruising after being knocked off his motorbike in traffic caused by one of the protests on November 9 2022, prosecutor Jocelyn Ledward KC said at the sentencing hearing at Southwark Crown Court.

All five defendants joined a Zoom call on November 2 2022 in which discussions were held about the planned protests, based off “what was said expressly and what could be inferred”, and were aiming to recruit others for the protests on the call, Ms Ledward told the court.

A journalist from the Sun newspaper, who had joined the call pretending to be interested in the protest, managed to record some of it and passed the recordings on to the police.

Judge Christopher Hehir said the Zoom call showed “how intricately planned the disruption was and the sophistication involved”, and was “compelling evidence” of the existence of a conspiracy.

There was “extensive organisation and planning” for the protests and each defendant had a “significant role” in the conspiracy, Ms Ledward said.

The defendants were convicted by a jury of conspiracy intentionally to cause a public nuisance, contrary to section 78 of the Police, Crime, Sentencing and Courts Act 2022 and Section 1 of the Criminal Law Act 1977, on July 11.

The defendants, referred to as the Whole Truth Five by Just Stop Oil on social media, spoke to confirm their names in court and shouted “We love you” from the dock immediately after the sentences were passed down.

Judge Hehir said: “The plain fact is that each of you, some time ago, crossed the line from concerned campaigner to fanatic.

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

Addressing Hallam, the judge said: “You are the theoretician, the ‘ideas’ man.

“In my judgment, you sit at the very highest level of the conspiracy.”

The judge told the court that 11 protesters were arrested on suspicion of contempt outside the court during the case’s trial on July 2, but the court had discontinued its proceedings against them on July 11 after he became “concerned” about their position.

Raj Chada from Hodge Jones & Allen, representing Hallam, Shaw and Whittaker De Abreu, said in a statement: “Today, the world was watching to see whether the UK will retain the hallmarks of a civilised society where non-violent direct action protestors will not be imprisoned. Today we are disappointed.

“Our planet is in emergency, and I hope the Government starts investing in tackling the climate crisis rather than prosecuting those that raise the alarm.

“We will be considering our options whether to appeal this ridiculous sentence.”

There have been no protests on the M25 since November 2022.