The environmentalists, including four dressed as tigers - Esso's advertising symbol - mounted the blockade in protest at global warming and U.S. opposition to the Kyoto protocol.
The protest was staged at Purfleet, near London, trapping up to 20 tankers inside the Esso depot. Esso is the British arm of U.S. oil company Exxon Mobil, the biggest in the world.

Police said that after lengthy negotiations, officers began physically removing protesters who refused to leave of their own accord.

"There are 41 men and women in custody. They were arrested on suspicion of conspiracy to commit criminal damage," a police spokeswoman said.

Greenpeace accused Esso of influencing U.S. President George W Bush's decision not to abide by the Kyoto pact.

Esso said this was a ridiculous suggestion. "There is no question that climate change is an important issue and one that we take very seriously," the company said in a statement.

Esso closed the depot during the blockade and suspended fuel deliveries. A company spokeswoman said the depot was a major part of Esso's British business