Climate activists who have caused chaos on the M25 were on Wednesday facing the threat of prison after ministers won an injunction banning them from continuing their “reckless” motorway protests.
The High Court order means that any protester who defies it will face detention for contempt of court and a potential prison sentence.
It also means that police will have the power to arrest and detain them to stop them returning to inflict more life-threatening disruption.
Wednesday’s injunction, which was obtained by National Highways on the instruction of Transport Secretary Grant Shapps and Home Secretary Priti Patel, follows days of protests on the M25 by activists from the group Insulate Britain.
The group has insisted that it has no desire to cause harm and claimed that it has no alternative but to pursue its campaign for homes to be insulated to combat climate change by taking direct action.
Mr Shapps rejected their argument, however, as he welcomed the court injunction.
“Invading a motorway is reckless and puts lives at risk,” he wrote on Twitter. “I asked National Highways to seek an injunction against M25 protesters, which a judge granted last night. Activists will face contempt of court with possible imprisonment if they flout.”
Ms Patel said the “important injunction” means “people can get moving again” on the UK's busiest motorway.
“We will not tolerate lives being put at risk,” she said.
“Those who continue to do so risk imprisonment.”
However the activists have indicated they will continue blocking the M25 despite the High Court injunction.
In a statement issued on Wednesday afternoon, Insulate Britain said that “right now our campaign goes on”.
“Currently 8,500 people a year die unnecessarily in the UK because of their frozen homes and climate collapse presents an incalculable threat to our way of life,” it said.
“A more measured way in which she could discharge her ministerial responsibility would be to ask the Prime Minister to start the process of insulating Britain’s leaky homes.
“As soon as the Government makes a meaningful statement that we can trust, we will leave the motorway.”
Police have already arrested around 90 people since the M25 protests began nearly two weeks ago, but have so far been unable to hold them because the offences do not carry a prison sentence.
That has allowed activists to continue causing disruption. By contrast, contempt of court is an imprisonable offence which means those held can be detained and face a maximum jail term of two years as well as an unlimited fine.
Assistant chief constable Chris Noble, the National Police Chiefs’ Council lead for policing protests, said he hoped that the injunction would help — and accused the activists of putting the lives of officers and the public in danger.
“Police aren’t anti-protest but we are pro-responsibility,” he said. “The people most likely to come to harm initially are police officers who are having to run across motorways to try to remove protesters as well as ironically to keep them safe from themselves.”
Zoe Cohen, from Insulate Britain, said campaigners “profoundly apologise for all disruption” and that putting lives at risk was “the last thing we want”.
She said they would consider how to respond to the injunction but added: “We are calling for the insulation and whole house retro-fitting of social housing by 2025 and all homes by 2030 because this is the most effective way to reduce emissions.”