Police made 30 arrests on Friday after activists disrupted traffic on three motorways in southeast England in a 10th day of direct action on climate change.
Protesters also targeted the M25 near Waltham Cross, Hertfordshire.
The group, an offshoot of Extinction Rebellion, is demanding that the government insulates all UK homes by 2030 to cut carbon emissions.
It says it will continue to take action until Boris Johnson's government gives “a meaningful statement indicating that they will insulate all of Britain’s 29 million leaky homes by 2030”.
The government said it was investing £1.3bn to support people to install energy efficiency measures.
Late last month ministers took out a high court injunction against the activists, threatening them with jail if they continued to disrupt traffic on the M25 or A20.
IB said Friday’s demonstrators included eight people released from police custody on Thursday, who defied the court order to block the M25 at junction 30 in Essex, and others arrested earlier this week.
Video and images posted on social media show activists sat in a row, glued together, blocking the M4 as frustrated motorists beep their horns at them as long queues formed.
In a statement following Friday's action, IB said: “It’s incomprehensible that the government is continuing to delay action on home insulation when we urgently need to cut our carbon emissions, eliminate fuel poverty and help hard-working families with their rising energy bills.
“Added to which industry is crying out for the government to show some leadership and get behind a national retrofitting strategy. Come on Boris: get on with the job.”
The Metropolitan Police said that the protesters blocked the M4 at around 8.27am. Officers were on the scene in 13 minutes and the road was cleared by 9am, with 13 people arrested for obstruction and conspiracy to commit public nuisance.
The M1 was cleared by 10am, with 17 people detained for the same offences. The force issued an update at 12.10pm stating that it was responding to the M25 protest.
Sir Stephen House, the deputy commissioner of the Metropolitan police, told the London assembly’s police and crime committee on Thursday that he was concerned police forces were under so much pressure to quickly clear the protests that “officers are putting their lives at risk”.
“The most recent one I saw had officers running between articulated lorries that were moving on the main carriageway of the M25,” he said.
“We cannot be doing that. We cannot put people’s lives at risk. My officers’ lives at risk and indeed the demonstrators’ lives at risk. We have to look out for that first. But we have been very quick in moving these people and arresting them.”
He added: “They started off on the slip roads, which is bad enough, but we’ve now moved on to the main carriageways of the M25, which is absolute lunacy.”
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