NHS England hospitals have sounded the alarm over materials used in roofs that reached the end of their lifespan more than a decade ago, with one hospital forced to restrict the use of some operating theatres to patients under 120kg (19st).

Several hospitals are warning of the potential for roof collapses due to structural weaknesses in the reinforced concrete planks used in their construction between the 1960s and 1980s, which have a 30-year lifespan.

North West Anglia NHS foundation trust wrote in its annual plan that the poor condition of the main theatres in Hinchingbrooke hospital in Huntingdon, Cambridgeshire, posed a significant risk to elective care.

The plan, published in June, stated: “There are a number of building-related issues, the most significant being the RAAC [reinforced autoclaved aerated concrete] panelling, which affects the loadbearing of the floor, restricting the use of some theatres to patients under 120kg.”

Since the report, more structural surveys have been undertaken and the hospital is able to use just one of its seven operating theatres for patients weighing more than 120kg. The hospital said it had received £13m this year to cover the costs of surveys and repairs.

Reports leaked by a whistleblower to the BBC showed that West Suffolk hospital, which has a similar design to Hinchingbrooke, had hired a law firm to investigate the potential for corporate manslaughter charges in the event of a fatal roof collapse, while hospital trusts in eastern England had produced an emergency plan outlining what would happen in the event of “significant hospital structural failure”.

The documents seen by the BBC included an initial risk assessment that warned of an “almost certain” plank collapse, which would have “catastrophic” consequences.

The risk level has since been downgraded to “likely” in response to West Suffolk launching a multimillion-pound safety works programme, though it is understood this will not be completed until spring 2023.

West Suffolk hospital in Bury St Edmunds has used 27 metal supports under concrete planks in the roof.

NHS England said the affected trusts were maintaining safe services and were regularly required to manage complex estates repairs, including roofing work. It added that training exercises were regularly conducted in the interests of safety and preparedness.

The problems relate to RAAC planks that were commonly used in the roofs, floors and walls of NHS buildings and schools between 1960 and 1980, that have since deteriorated or have structural weaknesses.

The BBC reported that West Suffolk hospital, in Bury St Edmunds, had 27 metal supports under the planks, while the Queen Elizabeth hospital in King’s Lynn in Norfolk had more than 200.

A spokesperson for NHS England and NHS Improvement East of England said: “Trusts in the east of England work in line with specialist industry advice and have been given more than £67m to help them manage their estates programme.

“Trusts have maintained safe services for patients, who should access hospital care as they normally would, and also introduced a number of measures including improved surveillance and use of specialist equipment to help identify and fix any issues immediately.”

Caroline Walker, the chief executive of the North West Anglia NHS trust, said: “Operations continue to take place for all our patients, and we are following expert advice to manage our estate, checking and surveying our buildings regularly and completing any maintenance as it’s needed.”