GREENPEACE protesters shut down BP petrol stations in Leyton and Walthamstow this morning.
The action was part of a co-ordinated London-wide protest by the group, which began at around 6.20am.
The Walthamstow garage in Forest Road has since re-opened, but the Leyton one, in the High Road, remains closed.
In a statement on its website, Greenpeace said small teams of activists had turned shut-off switches to stop the flow of fuel at each garage.
Protesters then removed the switches to stop the stations from re-opening.
The environmental campaign group said it shut down 46 BP stations across the capital, although many have since re-opened.
Explaining the motivation behind the protests, Greenpeace executive director John Sauven said: "The moment has come for BP to move beyond oil. Under Tony Hayward the company went backwards, squeezing the last drops of oil from places like the Gulf of Mexico, the tar sands of Canada and even the fragile Arctic wilderness.
"We've shut down all of BP's stations in London to give the new boss a chance to come up with a better plan. They're desperate for us to believe they're going ‘beyond petroleum'. Well now's the time to prove it."
A spokeswoman for BP said the company was working "as quickly as possible" to re-open the Leyton garage, but could not say when that would be.
She added: "This is an act of vandalism which puts the safety of motorists and our staff at risk.
"They've taken handles which we need to replace, which we're hoping to do as soon as possible".
The franchisee manager of the BP garage in Leyton declined to comment to the Guardian.
The protests were timed to co-incide with today's widely-predicted announcement that BP chief executive Tony Hayward is to leave the company in October.
The company also revealed today that it had lost at least £20.8billion due to the catastrophic oil spill in the Gulf of Mexico.