UK banks and building societies are required to make transaction histories available to customers in order to make switching banks easier and to address concerns that customers who switched would lose access to their banking history - a key requirement for lenders offering credit.

Bank of Ireland, NatWest Group, and Virgin Money also breached the CMA’s Order in a similar way, but on a much smaller scale than Monzo. In total, nearly 150,000 customers were not provided with their transaction history in the necessary timescale. Some transaction histories were provided a few weeks late, while others have been delayed by more than a year.

If the banks breach the order again, the CMA can take further action by issuing legally binding ‘Directions’. These could include banks having to introduce specific training or carrying out annual compliance audits to prevent this from happening in the future.

The CMA cannot currently impose financial penalties on businesses for breaches of this kind but has called for the power to do so.

Adam Land, CMA senior director of remedies business and financial analysis, says: “Nearly 150,000 people were affected by these banks’ breaches, with the majority being former Monzo customers. This may have made things harder for people trying to borrow money or apply for a mortgage.

“We will be watching closely to make sure these leading names stick to their word and don’t let their customers down again. The Bank of Ireland, Monzo, Natwest Group, and Virgin Money should be in no doubt that the CMA stands ready to take further action if these failures are repeated.”