Climate protesters caused major delays by blocking five junctions on the UK’s busiest motorway during rush hour on Monday morning.
Dozens of people were arrested following the demonstrations to demand Government action on home insulation.
The group Insulate Britain – an offshoot of Extinction Rebellion – staged sit down protests at Junction 3 for Swanley in Kent, Junction 6 for Godstone in Surrey, Junction 14 for Heathrow Terminal 5, Junction 20 for Kings Langley in Hertfordshire, and Junction 31 for Purfleet in Essex.
At least one driver attempted to drag a protester off the road.
The protest began at about 8am on Monday and took up to noon to be cleared.
Chief Inspector Paul Austin, of Essex Police, said: “This incident caused significant disruption and our officers worked to resolve it as quickly and safely as possible.
“I want to thank the drivers affected for their patience and understanding.”
Surrey Police said 36 protesters were arrested at Junctions 6 and 14.
Essex Police said it made 12 arrests at Junction 31, while Kent Police arrested the same number of people at Junction 3.
Insulate Britain describes itself as “a new group demanding that the Government gets on with the job of insulating Britain’s homes”.
Its website warned that Monday’s disruption was “just the start”, and “action will continue until the Government makes a meaningful commitment to insulate Britain’s 29 million leaky homes”.
One supporter, Liam Norton, a 36-year-old electrician from London, said he is “shocked at the lack of significant action from our Government”.
He went on: “It’s a no brainer. Insulating Britain will reduce emissions, provide hundreds of thousands of jobs and stop our elderly dying in cold homes each winter. So stop messing about, Boris, and get on with the job.
“As soon as a statement is made that we can trust and is meaningful, we will get off the roads.”
Another activist, Zoe Cohen, 51, from Warrington, Cheshire, said: “Boris needs to stop making things worse – with all their road building, airport expansion, HS2 white elephant and new oil fields – and get on with the obvious stuff like insulating the 29 million homes that need to come off fossil fuels.
“We can’t get to net zero if they don’t take responsibility for this. Only the Government can make this happen.”
AA president Edmund King said: “This action is not only incredibly dangerous in potentially putting lives at risk but it also backfires in environmental terms by causing more delays and more vehicle emissions.
“These are some of the busiest sections of the M25 where tens of thousands of drivers will have been affected and has a negative knock-on effect on economic activity.”
Sam from Bromley, south-east London, who did not wish to share his second name, said he was stuck in the traffic with his two young children for three hours.
The 37-year-old had been on his way for a day out at a farm on a “rare day” he has time for a trip with his family.
“I am seething at how irresponsible and selfish their demonstration is,” Sam told the PA news agency of the demonstration.
“It is ill-considered and poorly executed. I am all for change and reducing fuel poverty but there are more sensible ways to lobby and protest.”
National Highways head of service delivery for the South East Sean Martell said: “We work hard with police and other partners to limit the effects of protests on the strategic road network.
“We will do all we can to keep drivers up to date and on the move.”
The Prime Minister’s official spokesman said: “People have the right to protest freely but clearly they shouldn’t be doing anything which is either illegal or endangers the public.”