Fourteen Just Stop Oil protesters were arrested during a slow march to block traffic at Parliament Square on Thursday morning during rush hour.
A group of 41 activists with the eco group began marching along The Strand at around 8.30am, causing “serious disruption”.
The group said around 12 activists were later arrested at Parliament Square. Police put the figure at 14 arrested.
A Scotland Yard spokesperson said: “At 09:15hrs, police put a section 12 condition on Just Stop Oil, now at Parliament Square, to move out of the road to stop disruption to traffic.
“At 09:19hrs, 14 people who stayed in the road were arrested for breach of S12 condition. The road is now clear.”
These orders are used when a senior officer believes it is necessary to prevent a procession from causing “serious public disorder, serious criminal damage or serious disruption to the life of the community”.
Protesters earlier blocked traffic at the Strand, then temporarily at Whitehall, before moving on to King Charles Street and Parliament Square.
A Just Stop Oil spokesperson said: “Your government has taken away your right to peaceful protest. If you are not outraged by this, you are not paying attention.
“If we tolerate the crushing of peaceful dissent, regardless of whether we agree with each other or not, we no longer live in any sort of functional democracy.”
The group is in its third week of daily direct action in its bid to end new oil and gas licences.
On Wednesday, around 32 activists with the group blocked Moorgate after marching through the City from Queen Victoria Street near Mansion House.
Earlier this week, the group also walked slowly in front of traffic in Camden, holding up banners reading “Just Stop Oil”.
Just Stop Oil estimates that since February 14 last year, some 2,100 arrests have been made in connection with the group’s activities.
