Barclays customers in switch threat over tar sands investment

Up to 30,000 account holders sign petition against pipeline projects in US and Canada

Thousands of Barclays customers have threatened to switch to another bank unless it promises not to invest in pipelines for oil from tar sands, dubbed the "dirtiest fuel on the planet".

Greenpeace, which occupied a branch of Barclays on Wednesday morning and erected signs branding it "The Dirty Bank", said 30,000 customers signed a petition calling on the lender to pledge never to fund controversial tar sands projects.