Hundreds of demonstrators claim they have stopped 375,000 gallons of fuel from leaving a depot after blockading the road to an oil refinery.
Police were forced to close the road after 12 women handcuffed themselves to lorries parked to deliberately block the main road leading to the Coryton refinery in Essex.
Demonstrators drove the vehicles to the refinery in an attempt to stop traffic getting to and from the site, which they accuse of exacerbating climate change.
A spokesman for the Crude Awakening demonstrators claimed 500 protesters blocked the road to the UK’s busiest oil depot near Stanford-le-Hope.
She said at least 50 oil tankers had been prevented from getting to and from the site.
Campaigners, some wearing fancy dress, also set up another blockade obstructing the entrance to Shell Haven Oils Site further down The Manorway, the spokesman said.
Protesters gathered earlier at three railway stations in central London in preparation to move on to a series of targets related to the oil industry.
Police searched protesters at Fenchurch Street station in London.
One of the protesters, Terri Orchard, said: “We don’t have a hope of tackling climate change if we don’t find a way to start moving beyond oil.
“We are here at the source of the problem, at the UK’s busiest oil refinery, to stop the flow of oil to London. We’re here to put a spanner in the works of the relentless flow of oil and to say no more. This place, this whole industry, must become a thing of the past.”
The demonstration was supported by a number of action groups, including Camp for Climate Action and Plane Stupid. It is part of a global week of action against the fossil fuel industry.
Essex Police described it as “a peaceful protest” and added: “Police will facilitate peaceful protest but will enforce the law where necessary.”
The protesters remained on the road for more than seven hours before they decided to leave, a spokeswoman for Crude Awakening said.