The bank failed to ‘properly oversee and manage’ systems aimed at verifying information provided by its business customers over a five-year period.

Between 31 December 2012 and 18 October 2017, the failings affected the oversight of accounts held by more than 560,000 business customers, leading to more than £298m passing through the bank before it closed accounts.

According to the FCA, Santander failed to ‘take into account important information’ regarding the anticipated turnover of a Business Banking customer, alongside failing to take reasonable care to organise and control its affairs ‘responsibly and effectively’.

In one case, a new customer opened an account in May 2013 with an estimated monthly account turnover of £5,000 - no referral or enhanced checks were made.