Banks are planning to board up branches in central London and run their operations with a skeleton staff because of the fear of violence around the G20 summit.
The news comes after protesters circulated a map which identifies more than 125 targets across the City, including dozens of international corporations, banks, and oil companies.
More than 50 financial institutions are pinpointed, including some of those – like Royal Bank of Scotland, Lloyds TSB – blamed for precipitating the current economic crisis.
The map urged potential demonstrators to vent their anger at the “carpeted, warmed and well-lighted offices” of corporate capitalism, quoting the writer CS Lewis’s attack on the “managerial age”.
None of the main banks would comment. However senior banking figures told telegraph.co.uk that they were taking the security threat seriously, and admitted that they were concerned about the possibility of trouble.
One banking source said: “Everyone is taking precautions in the Square Mile. Many branches will be closed. It will be essential staff only who travel into work in those two days.
“Lets hope that it goes off peacefully. We cannot guarantee that but we hope it will be the case.”