The Body Shop has said it will become the first company to publicly back a boycott of Esso service stations in protest at its parent company's support for the US withdrawal from the Kyoto climate change pact.
Esso is the European brand of ExxonMobil.
Body Shop says its fleet of lorries will not fill up at Esso garages. It is urging its 2,500 British staff to do the same and will publicise the boycott in all its 229 British stores.
Since its launch two months ago the campaign has drawn support from members of the European Parliament. Pop star Annie Lennox and actor Ralph Fiennes have also been vocal supporters.
The Kyoto Protocol calls for industrialised nations to cut carbon dioxide emissions by 5.2 per cent from 1990 levels by 2012, but President Bush pulled the United States - the world's biggest greenhouse gas emitter - out of the treaty.
ExxonMobil has not accepted scientific evidence that fossil fuel emissions cause global warming, campaigners say, and is a member of the Global Climate Coalition, an international business lobby set up to counter that view.
The company says it supports the study of climate change and has invested over $500 million in renewable energy.
Greenpeace, one of the founders of the Stop Esso Campaign, is also targeting Chevron, Texaco, Conoco and Phillips in its efforts to influence consumers.