A police officer has been injured in a lorry crash during a third morning of Just Stop Oil protests on the M25.
A rolling roadblock had been put in place between Junction 26 and 27 on the Kent-bound stretch leading to the Dartford Crossing after a person was spotted trying to access a gantry.
There was then a crash involving two lorries and a police motorbike.
Two people have been arrested on suspicion of causing a public nuisance.
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.
“Our roads policing officers are dedicated, specialist officers who come to work to serve the public and keep you safe on our roads.
“They do this tirelessly, day-in day-out.
“Sadly, this morning one of these fantastic officers has been injured while carrying out this work.
“My thoughts are with them and their family. I want to thank the public for their support, patience and understanding while we work to resolve this situation.”
Separately protesters scaled gantries at junction 30 and 29 leading to the closure of the road.
Essex Police has arrested the junction 30 protester and brought down the protester on junction 29 a few moments ago.
Kent Police has arrested two people: a 71-year-old man from Cornwall and a 75-year-old woman from Somerset. They remain in police custody.
Just Stop Oil supporters have climbed gantries at multiple locations along the motorway, including another near the Swanley turn off.
The M25 clockwise is blocked, with long queues between J4 (Orpington) and J5 M26 / A21 (Sevenoaks).
Traffic is also backed up to Junction 28 in Essex after the protest at Junction 30, just before the crossing into Kent.
There is currently congestion stretching back to J2 A2 (Darenth Interchange, Dartford).
Kent Police tweeted an update at 8.24am, saying: "We have arrested the protester who climbed onto an overhead gantry close to junction 4 of the M25 and are now reopening all lanes of the motorway."
From 6.30am around 10 supporters of Just Stop Oil climbed onto the gantries of the motorway, both clockwise and anti-clockwise.
This is part of their campaign to demand that the government halts all new oil and gas licences.
Sam Holland, a former student from Leeds, is one of the protesters who has taken part in the demonstration.
The 20-year-old said: “I’m taking action because I have no choice.
"If governments across the world are allowed to drill for more oil and gas, we face a future of crop failure, starvation and social collapse. Civil resistance and mass disruption gives us a chance of forcing them to change.
"I am risking prison time but I’m willing to do that because prison is nothing compared to what is coming down the road. I will not sit by and do nothing whilst this horror unfolds.”
Just Stop Oil have also confirmed that they have been joined by supporters of Animal Rebellion.
A fourth person has been arrested and all parts of the M25 in Essex are now open.
Essex Police brought the protester down from a gantry at junction 29 and National Highways have re-opened all lanes.
Chief Superintendent Simon Anslow said: “I want to thank the public for their support, patience, and understanding this morning.
“I know they’re frustrated and I share those frustrations. You just want to get to work, make your hospital appointment, take your children to school.
“Already this week we’ve heard how grieving families have been prevented from saying goodbye to a loved one. And this has all been done while the safety of the public and our officers is being put at risk.
“We will continue to work to resolve these situations as quickly as possible to keep Essex moving and take action where crimes are being committed.”
A total of 16 activists were arrested yesterday as part of the joint operation with Kent, Essex, and Surrey Police forces.
At 8am yesterday, a man climbed onto the overhead gantry at junction 14 of the M25.
It led to road being closed, interrupting traffic and causing significant disruption around Heathrow.
Met officers responded quickly, arriving on the scene at 08.10am and by 8.30am the man was removed and arrested.
He was taken into custody at a south London police station and the road reopened at 8.46am.
Assistant Commissioner Matt Twist said: “The Met, in a joint operation with neighbouring police forces, has again responded swiftly and robustly to today’s attempts by Just Stop Oil activists to disrupt the M25.
“We are all absolutely committed to providing a quick and effective response to those activists who continue to significantly disrupt people’s daily lives.
“Operations like these come at a cost. Since the start of October we have used more than 11,000 officer shifts to police Just Stop Oil protests. These are officers who would otherwise be dealing with issues that matter to local communities such as knife crime, safeguarding and responding to burglaries.
“We are determined to bring to justice all those who conspire to cause significant and unreasonable disruption to London and the motorway network and we'll work closely with the Crown Prosecution Service and the courts to make sure this happens.”
In total, 22 people have already been charged as part of this ongoing operation.
These include Charlotte Kirin, 53, of Peckham Street, Bury St Edmunds and 55 year-old Paul Bleach, of Locarno Road, Portsmouth.
Both protesters have been charged with intentionally recklessly causing a public nuisance.
They were arrested at junctions 31 and 27 of the M25 respectively and are due to appear at Westminster Magistrates' Court today.
Theresa Norton, 54, of Esplanade Gardens in Scarborough, North Yorkshire, was charged with intentionally or recklessly causing a public nuisance. This relates to the incident at junction 1A. Ms Norton appeared at Westminster Magistrates’ Court on the same day.
And today, Lucia Whittaker-de-Abreu, 33, of Arthur Street in Derby and Molly Berry, 70, of Lower Icknield Way, Marsworth, Buckinghamshire, both charged with intentionally or recklessly causing a public nuisance, were due to appear at Westminster Magistrates’ Court.