Protesters are causing widespread disruption on the M25 for a second day after several junctions were blocked.
Just Stop Oil said “approximately 15” of its supporters climbed on to overhead gantries in “multiple locations” on the UK’s busiest motorway from 7am on Tuesday, causing police to halt traffic.
The Metropolitan Police said 16 protesters were arrested in a joint operation with neighbouring forces, including Essex Police, Surrey Police and Kent Police.
Meanwhile, eight people charged with conspiracy to cause a public nuisance following protest action on Monday are due to appear at Westminster Magistrates’ Court.
On Tuesday, Essex Police said a protester climbed on to the gantry at junction 31, causing the Dartford Tunnel to be closed.
The force said: “Specialist officers were mobilised quickly and managed to bring the woman down and arrest her within 90 minutes of her being spotted.
A Just Stop Oil protestor climbed a gantry on Tuesday Just Stop Oil
“As a result, the tunnels at the crossing were closed but one has since reopened.”
National Highways said there were delays of an hour, with congestion for five miles.
Just Stop Oil also targeted at least six other locations on the M25.
The Met's 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.
National Highways said there were delays of an hour, with congestion for five miles. Just Stop Oil
“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.”
Protests took place at 13 locations on the M25 on Monday.
Police believe some of those involved in the demonstrations could have breached a High Court injunction obtained by National Highways.
Just Stop Oil said in a statement: “We will not be intimidated by changes to the law, we will not be stopped by private injunctions sought to silence peaceful people.
“Our supporters understand that these are irrelevant when set against mass starvation, slaughter, the loss of our rights, freedoms and communities.”
'Are you thinking you're above the law?'
Mark Longhurst challenges Just Stop Oil spokesperson Lora Johnson as protestors bring large parts of the M25 to a halt for the second day in a row. pic.twitter.com/cbjxyrM3rK
The Met is conducting an operation to foil the protests in conjunction with the National Police Coordination Centre.
Just Stop Oil staged 32 days of disruption from the end of September and throughout October, which the Met said resulted in 677 arrests with 111 people charged, and officers working a total of 9,438 additional shifts.
According to the group, Just Stop Oil supporters have been arrested nearly 2,000 times since its campaign began on April 1, and five are currently in prison.
It warned the Government’s refusal to halt North Sea oil and gas extraction will contribute to global warming, which “will result in the collapse of ordered civil society, the loss of our rights and freedoms and the death of countless millions of people”.