A cross-party group of MPs has written to the head of the Financial Conduct Authority to criticise a decision not to take action against the Royal Bank of Scotland for the mistreatment of small businesses.

Kevin Hollinrake, co-chair of the All-Party Parliamentary Group on Fair Business Banking, wrote to Andrew Bailey, chief of the FCA, in response to a statement from the regulator in July, in which it said it did not have the power to bring enforcement action against RBS over the way its Global Restructuring Group dealt with small businesses after the 2008 global financial crisis.