Royal Bank of Scotland is under fierce attack for investing hundreds of millions of pounds in US companies that remove the tops of mountains to get at coal inside.

More than 500 mountain summits have been removed by explosives in the Appalachians, West Virginia, over the past few years. The process releases toxic waste into streams, pollutes the air and threatens the health of local communities.

RBS has been named as the world's seventh-biggest financial backer of mountaintop removal (MTR), with £235.6 million of lending and underwriting in 2012.

A number of major American mining companies have benefited from RBS money.

The bank is set to come under fire for funding such large-scale environmental destruction from protesters at its annual general meeting, at Gogarburn, Edinburgh on Tuesday.

Paul Daly, corporate accountability campaigner with Friends of the Earth Scotland, said: "RBS is still financing corporations which undertake horrific operations like MTR, threatening the local environment and adding to climate change globally."

Extreme Investments, a report on the US coal industry by the Rainforest Action Network, Banktrack and green group the Sierra Club, lists RBS along with Citigroup, Barclays, Morgan Stanley and others as the main backers of MTR.

RBS is reviewing its policies and approach to MTR companies. A spokeswoman said: "We apply enhanced environmental and social due diligence to our clients involved in MTR, and engage with them on how they can meet positive standards of corporate responsibility."