Environment activists used fire extinguishers to spray paint at the Secret Intelligence Service’s headquarters in London on Monday, as well as at the Home Office, the Bank of England and the News Corp offices.
In footage posted on social media by Just Stop Oil, a member of the public can be seen intervening in the activism outside MI5.
The man tussles with an activist, as he tries to wrench a paint-spraying device from their hands.
At one point, the man appears to shove the protester and can be seen pulling off their baseball cap which he throws to the ground.
The protester continues trying to spray the building, and both they and the passer-by are too left covered in orange paint.
Londoners have been warned by the Met not to “directly intervene” with disruptive Just Stop Oil protesters.
Assistant Commissioner Matt Twist urged people not to take the law into their own hands after activists blocking roads in London were dragged out of the way in heated scenes on Saturday.
Six people have been arrested by the Met Police on suspicion of criminal damage and taken into custody at a central London police station following Monday’s protests.
City of London Police officers arrested a further two people who sprayed the Bank of England.
Just Stop Oil said the buildings it targeted were chosen to represent “the four pillars that support and maintain the power of the fossil fuel economy — government, security, finance and media”.
It is the latest in a month-long stint of daily protests that has seen protesters stage sit-ins, block off key London roads, and vandalise buildings as they call on the Government to end all new oil and gas projects by 2025.
The environmental campaigners caused huge build-ups of traffic on Saturday afternoon by sitting in the middle of streets including Kensington High Street, Charing Cross Road, Kennington Park Road and Black Friars Road.
A Just Stop Oil spokesperson said: “We are not prepared to stand by and watch while everything we love is destroyed, while vulnerable people go hungry and fossil fuel companies and the rich profit from our misery.
“We are acting to stop new oil and gas because it is the right thing to do. As citizens, as parents we have every right under British law to protect ourselves and those we love. The government has the power to end the disruption today by agreeing to stop new oil and gas licences and consents.”