Insulate Britain protesters attempted to block the M25 at the South Mimms roundabout at Junction 24 on Tuesday morning.
Six of the demonstrators were stopped by police from getting into the road at about 8am.
They instead sat on the pavement with a banner. Some have glued themselves to the surface.
One man has been detained at the scene.
Police have begun carrying Insulate Britain demonstrators away from their protest at a junction of the M25.
A group of officers have been lifting activists from the pavement beside the road at Junction 23 and putting them in the back of a van.
More than a dozen officers and seven police vehicles are on scene.
Some passers-by were heard shouting expletives at the protesters.
Nine Insulate Britain demonstrators have received committal papers in relation to an injunction granted to National Highways to curb eco-activist roadblocks, an Insulate Britain spokesperson has confirmed.
Diana Warner, 62, a retired GP, said: “One of the important reasons for coming out today was to say we’re all together. It’s not just nine.”
