According to spending watchdog the National Audit Office, the staggering figure highlights the urgent need for a comprehensive strategy to manage assets, alongside long-term investment planning.

The NAO found that properties owned by the Ministry of Defence, schools, and the NHS account for more than £10bn each in backlog costs, making up 88% of the total.

The remaining 12%—estimated at less than £2bn per sector—covers a wide range of sites, including prisons, courts, museums, and job centres.

Departments blamed the mounting backlog on rising costs of repairs, alongside deterioration of multiple buildings, lost income during the pandemic, and years of underinvestment.

Even by the Cabinet Office’s own estimates deferring maintenance could increase costs by more than 50% within just two to four years, warns the NAO report.

NAO head Gareth Davies warned against the financial risks of continued neglect.

He said: “Allowing large maintenance backlogs to build up at the buildings used to deliver essential public service is a false economy.

“Government needs better data on the condition of its operational assets and should use it to plan efficient maintenance programmes to deliver better services and value for money.”

The report says there is now a critical need for decisive action to safeguard public services and improve the condition of the UK’s vital infrastructure.

The effects of deteriorating infrastructure are already being felt. From 2019-20 to 2023-24, the NHS reported an average of 5,400 clinical service incidents annually due to property and infrastructure failures.

The NAO has also recommended several measures, including:

• Standardising the definition of maintenance backlog across departments.
• Including backlog data in the State of the Estate report starting in 2026-27.
• Developing long-term property plans to address capital needs and reduce backlogs.
• Exploring longer-term funding settlements and ring-fenced maintenance budgets.