Britain’s largest banks accumulated the equivalent of more than a full month of unplanned IT outages over the past two years, as aging legacy infrastructure continues to fail under the weight of modern digital banking demands.
Data published by the UK Treasury Select Committee revealed that nine major banks and building societies – including Barclays, HSBC, Lloyds, Nationwide, Santander, and NatWest – experienced at least 803 hours of service disruptions between January 2023 and February 2025. The 158 separate incidents left millions of customers unable to access their accounts, make payments, or use banking apps.
The outages are not isolated glitches. They are symptoms of a deeper structural problem: UK banks are spending approximately £3.3 billion ($4.4 billion) annually – 24% of their entire IT budgets – simply maintaining outdated core banking platforms, according to September 2025 research from banking technology firm SaaScada. More than half of the 150 banking leaders surveyed described their core platforms as a “bottomless pit” for time and money.
The cost of failure is accelerating. A November 2025 survey by financial services consultancy GFT found that the average major IT outage now costs UK investment banks more than £600,000 ($805,000) per hour. Institutions reported approximately four major customer-facing outages in the past 12 months.
Dame Meg Hillier, Chair of the Treasury Select Committee, described the impact on customers bluntly: “For families and individuals living paycheck to paycheck, losing access to banking services on payday can be a terrifying experience.”
The banks attributed the failures to a familiar trio of causes: problems with third-party suppliers, disruption caused by system changes, and internal software malfunctions. None of these are new problems, and none are being solved by the current level of investment in modernization.
The contrast with digital-only banks is stark. Monzo’s chief technology officer, Matej Pfajfar, said the recurring outages at traditional lenders fall “well below the level of service that the industry should be providing, and that customers rightly expect.” While challenger banks built their infrastructure from scratch on modern cloud architecture, incumbents remain tethered to mainframe systems that were designed for an era when banking was branch-based and batch-processed.
Steve Round, president of SaaScada, warned that the status quo is not sustainable: “Legacy core systems are breaking, and things will only get worse. For some banks, it could potentially be game over.”
Sources: Why UK banks keep breaking down: the data problem hiding in plain sight (TechRadar, July 23, 2026); More than one month’s worth of IT failures at major banks (UK Parliament Treasury Committee, 2025)