Tens of millions of pounds of urgent repairs need to be carried out at the Royal Free NHS Foundation Trust in order to prevent “catastrophic” failures and risk to safety.

The Royal Free Trust has a backlog of £65.8million of repairs or replacements that should have been carried out on its buildings and equipment. About £8.7m worth of the outstanding jobs are classed as “high risk” repairs.

This means they could cause “catastrophic failure, major disruption to clinical services or deficiencies in safety liable to cause serious injury and prosecution” if not addressed immediately.

Director of Camden Healthwatch, Frances Hasler said the bill, along with the Royal Free’s deficit showed a “trust under strain.”

“This is building up a picture of a trust that is under strain in all kinds of ways.”

The figure covers the Royal Free Trust sites in Hampstead, Barnet and Chase Farm. Out of the trio, the Hampstead site has the highest bill; accounting for £7.8m of the most urgent repairs, and £37.05m of the overall sum. The total is among the highest in north London, with only London North West Healthcare NHS Trust needing to spend more: £207m.

Elsewhere in London, the highest amount is Imperial College Hospital with £696m needing to be spent.

Examples of maintenance required could include upgrading software on medical equipment, maintaining generators and boilers, and ensuring the structural integrity of buildings.

The Royal Free Trust told this newspaper the costs were “typical” of a hospital of its size. It said costs partially come from “key electrical infrastructure upgrades and theatre refurbishment works,” which have already been completed this year.

It is set to upgrade its fire safety systems, and will be spending £1.75m in the first year of a three-year plan to tackle urgent repairs.

Last year the trust spent £4.2m catching up on work. The bill continued to swell, however, rising by 29 per cent compared with the previous year.

Since 2013-14, the total bill has risen by 237pc. The “high risk” repair bill has increased by £6m, having stood at £2.5m in 2013-14.

According to a recently published report by NHS Digital, which covers the 12 months to March, problems with the trust’s infrastructure led to 225 incidents where patients were either harmed or put at risk of harm. There were 17,900 incidents across England during the same period, an increase of 800 in a year.

Clinical services were delayed, cancelled or otherwise affected because of problems with buildings or facilities on two occasions.

Ms Hasler has said the bill is part of a wider picture. She said: “It’s concerning. In common with other trusts up and down the country, the Royal Free also finished the last financial year with a big deficit which is a contrast to a few years ago.

“Nationally, NHS England has raided capital budgets on a national level to prop up the day to day spending and that has been happening everywhere.”

A spokesperson for the Royal Free Trust said: “It said: “The clinical areas of the hospital are very heavily utilised and it is necessary for a backlog of maintenance to accumulate in order to warrant closing an area to carry out planned refurbishments.”

“The safety of staff and patients is our utmost priority. We set ourselves very high standards and constantly inspect and risk assess our buildings to ensure they comply with these expectations. There will always be improvements which can be made when managing large buildings and we address these in order of priority.”

The repair bill across England reached a record £6bn at the end of March.

It has risen every year since 2011-12, when it stood at £4bn, while costs for outstanding “high risk” works have more than tripled over the same period.