The fallout from TSB's recent IT meltdown continues, with customers who complained about the fiasco being sent letters containing information about other people - a mistake which could put the bank foul of new data protection laws.
After April's migration to a new banking platform from parent Banco Sabadell went spectacularly wrong, hordes of angry TSB customers filed complaints with the bank.
But, some letters sent out by TSB acknowledging these complaints mistakenly contained an extra letter with the name, address and reference number of another customer, according to the BBC.
A bank spokesperson says: "We are aware that there has been issue with a recent acknowledgement mailing. We are working with our third party supplier to understand the root cause of the error and we'd like to apologise to anyone that may be impacted."
MP John Mann, a member of the Treasury Select committee told the BBC: "They have broken the law. Even a small or minor breach of the law when it comes to data protection, is very, very important."
With new General Data Protection Regulation rules now in place, Mann added: "There is a danger action could be taken against the bank."
Data protection is a major concern in the wake of the IT disaster, with TSB customers reporting a surge in phishing activity as criminals take advantage of the chaos and confusion surrounding the UK bank's botched platform switch.
Meanwhile, sim swapping - where crooks take over someone's mobile phone so they can get an authorisation code from a bank - has been reported, with one victim telling the BBC he had £13,000 stolen from his account.