The Financial Services Authority (FSA) said its investigation found an unacceptably high risk that customers may not have been treated fairly due to multiple failings in 2009 in the banks’ approach to routine complaint handling.
Margaret Cole, the FSA’s managing director of enforcement, said the poor performance at the majority state-owned bank came to light during a review of major lenders.
“We expect firms to treat customers fairly and that consumers can be confident that their complaints will be dealt with properly,” Cole said.
The watchdog published a consultation paper last September on improvements to complaint handling procedures and said RBS and NatWest agreed to make significant changes.
RBS and NatWest also agreed to settle at an early stage, so qualified for a 30 per cent reduction in penalty.
“We recognise the importance of complaint handling for our customers and are focused on addressing the root causes of complaints,” said Brian Hartzer, chief executive of RBS Group’s UK retail operations.
Consumer lobby Which? said the case was evidence of banks failing customers and RBS and NatWest should compensate customers that have lost out.