The group, whose members are calling on the government to help insulate homes to reduce emissions, blocked junction 18 of Britain’s busiest motorway on Monday morning.
Images posted by the campaign group on social media showed a small group of protesters dressed in high-vis jackets blocking an exit slip road in Chorley, Hertfordshire.
In a tweet, the group said that blue paint had also been poured onto the road “leading to further disruption”.
Hertfordshire Police confirmed that officers were called to reports of protesters near Junction 18 at 8.12am today, as well as a separate demonstration near J4 (Stanborough Interchange) of the A1M.
A spokesperson for the force said twenty-nine people had been arrested on Monday morning and officers remained at the scene “to resolve the disruption as quickly as possible”.
The protest on Monday morning comes just hours after the group wrote to National Highways asking for speed limits to be reduced.
A statement from the group read: “Insulate Britain are asking the Highways Agency to review their previous decision not to reduce speed limits, even though they had been made aware that major disruption will be taking place.
“Given that this is a standard safety procedure when hazards occur on the motorway, Insulate Britain is surprised it has not formed part of the response to the campaign.”
In its letter, the group said it is “entirely proportionate to create disruption on the motorway network if it means the UK Government fulfils its legal obligation of staying below 20C which will stop the unimaginable suffering for future generations”.
Dozens of activists were arrested last week as protests brought disruption to parts of the South East. Protests blocked several parts of the M25 in Kent, Essex and Hertfordshire, including Junction 9 in Leatherhead, and Junction 6 in Godstone.
The group has said that its actions will continue until the government makes a “meaningful commitment to insulate all of Britain’s 29 million leaky homes by 2030, which are among the oldest and most energy inefficient in Europe.”
Chief Superintendent Nick Caveney, of Hertfordshire Police, said the force had made 79 arrests in relation to protest activity in the past week.
“Not only is purposely blocking a highway incredibly dangerous, it also affects thousands of members of the public who are stuck in delays as a result,” she said.
“We have robust plans in place in order to minimise any disruption and to allow us to make arrests as quickly as we possibly can.”
Home Secretary Priti Patel is said to have told police to take “decisive” action to crack down on the protests which brought traffic to a halt.
Met Police Deputy Assistant Commissioner Laurence Taylor previously said: “The actions of this group have significantly impacted the major road network around London.
“Removing individual protesters who have glued themselves to the road or locked themselves on to something is a complex and resource-intensive challenge and we must do this in a safe and effective way.”
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