A decade-long failure to address urgent repairs in hospitals across England has led to a dramatic rise in issues posing a “high risk” to patients and staff, ministers are being warned.

The cost of dealing with this backlog has almost tripled since 2015 in real terms, to £2.7bn this year. High-risk repairs have been the fastest growing part of the lengthy maintenance list over that time. It includes issues that could lead to serious injury to both staff and patients, or to major disruption of services or “catastrophic failure”.

The NHS lost more than 600 days – or 14,500 hours – of clinical time because of infrastructure failures in the last year, according to a new analysis seen by the Observer. The total maintenance backlog has now ballooned to £13.8bn in 2023-24, an 18% increase from last year. The figure is more than the NHS’s entire capital budget for the year.

There were 22 incidents of lost clinical time a day on average, according to the analysis of official data by the House of Commons library. Close to 80% of the time lost was due to incidents deemed to have the most clinical impact, including faulty roofs, water leaks, and broken lifts or heating systems. There were 1,584 “critical incidents” recorded, the most severe kind.