(Credit: George Iordanov-Nalbantov)

Up to 447,936 customers across Lloyds, Halifax and Bank of Scotland experienced unauthorised transactions appearing in their accounts, or had their personal data inadvertently shared with other users. Of those, around 114,000 customers clicked on exposed transactions belonging to other account holders, potentially viewing sensitive information including account details, national insurance numbers and payment references.

The full scale of the incident has emerged following pressure from the Treasury Select Committee, which demanded transparency from the banking giant. In a letter published this week, Lloyds’ chief executive of consumer relations, Jasjyot Singh, confirmed the bank had made goodwill payments totalling more than £139,000 to over 3,600 customers.

Dame Meg Hillier, chair of the treasury select committee, acknowledged the broader implications of the incident, warning that the shift towards digital banking requires customers to place their trust in technology that remains vulnerable to unpredictable failures. She stressed that banks must be transparent when such errors occur.

The glitch, which took place on 12 March, has drawn scrutiny from regulators and legal experts alike. Lawyers have warned that Lloyds could face a substantial fine and investigation, as the inadvertent exposure of financial data may constitute a reportable breach under UK data protection law, triggering obligations to notify the Information Commissioner’s Office (ICO). The ICO has confirmed it is aware of the incident and is making enquiries.

Mr Singh stated that Lloyds has notified the Financial Conduct Authority, the Prudential Regulation Authority and the ICO, and confirmed the bank would cooperate fully with all relevant authorities.