Protesters picketed an Oxford petrol station as part of an environmental campaign.

Barbara Hack and Chris Williams, of Oxford's Greenpeace group

They were urging motorists at the Esso petrol station in Oxpens Road on Saturday to boycott the company because they claim its environmental policies harm the planet.

Greenpeace, Friends of the Earth and student environmental group People and Planet have joined forces for the international campaign.

They claim Esso does not see global warming as important, refuses to invest in renewable energy and has undermined international action against climate change by backing George W Bush's opposition to the Kyoto environmental agreement.

Esso spokesman David Eglinton said: "Esso takes the matter of climate change very seriously and we are actively working to reduce the risk it poses. The accusations made by Greenpeace and Friends of the Earth are groundless."