A police officer has been injured in a collision involving two lorries while responding to Just Stop Oil protests taking place on the M25.
Essex Police said one person has been arrested for causing a public nuisance for protesting on the motorway, though the cause of the accident is unclear.
The force said a police officer was struck and injured by a vehicle after a rolling roadblock was put in place due to a person being on the road.
It added the incident has led to road closures between Junction 26 and Junction 27 clockwise.
There have been further reports of people on gantries near Junctions 29 and 30, with Essex Police bringing down and arresting one protester who was scaling a gantry on Junction 30.
Motorists have been urged to avoid the area and seek alternative routes while several police forces deal with the demonstrations.
Chief Superintendent Simon Anslow said: “Officers have again responded quickly to minimise disruption and two people have already been arrested.
“One of our officers has been injured as they worked to help resolve this situation.”
It comes after Just Stop Oil said around 10 of its supporters had climbed onto overhead gantries in “multiple locations” on the M25 from 6.30am on Wednesday – the third consecutive day of protests on the UK’s busiest motorway.
The protesters have also been joined by Animal Rebellion activists – who are campaigning for “a plant-based food system”.
Officers are warning the ongoing action would cause disruption to traffic in the area.
Elsewhere, Surrey Police confirmed one protester was on a gantry near Junction 8 on the motorway.
The force said: “Officers are proactively patrolling the rest of the M25, as they have been all week.”
The M25 was closed between Junctions 7 and 8 clockwise.
Kent Police said officers have been responding to a report of protesters close to Junction 4.
The Metropolitan Police said on Twitter: “We’re ready to respond to any protest activity on M25 with partner forces again today.
“We know this disruption is incredibly frustrating for the public.”
The force added that officers are currently on scene at Junctions 24 and 25, where a protester “has locked themself on to a gantry”.
It added that locks add “more complexity for our removal teams” so officers have had to bring in specialist equipment for the removal, including a JCB.
Just Stop Oil said in a statement: “This is not a one-day event, expect us every day and anywhere.
“This is an act of resistance against a criminal government and their genocidal death project.
“Our supporters will be returning today, tomorrow and the next day, and the next day after that, and every day until our demand is met: no new oil and gas in the UK.”
National Highways has secured a High Court injunction to prevent Just Stop Oil protesters from disrupting England’s busiest motorway.
The court has granted a further injunction that aims to stop unlawful demonstrations on the M25, which encircles Greater London, in an attempt to end the disruption to the busy road by the environmental group.
Just Stop Oil staged 32 days of disruption from the end of September and throughout October, resulting in 677 arrests and 111 people charged, with Met Police officers working a total of 9,438 additional shifts.