A trust at the centre of the largest maternity scandal in NHS history has revealed it lost historical data during routine IT work, with police now assessing its impact.

Maternity records of women and babies who received care between September 2011 and November 2022 were overwritten during work at Nottingham University Hospitals (NUH) NHS Trust.

Information has been restored since the “human error” on 18 August, but the trust has not been able to restore the history showing who viewed maternity records during this period.

A police probe last year into a missing data file containing the details of hundreds of maternity cases found it was most likely deleted “intentionally or maliciously”.

Nottinghamshire Police has been notified of the data incident and is assessing whether there has been any impact on Operation Perth – the investigation into deaths and injuries related to maternity care at Nottingham City Hospital and Queen’s Medical Centre, the main two hospitals run by the trust.

The force said it was told of the data loss on 4 September, and officers attended NUH on 7 September to establish what happened and how, to consider any potential criminal offences and to find out if the lost data could be recovered.

Deputy Chief Constable Rob Griffin, gold commander for Operation Perth, said: “At present, no crime has been identified. We have received a report from the individual concerned and have spoken with them.

“Further assessment is ongoing, and we are awaiting analysis of the digital process that was used.

“In relation to recovery, we are awaiting a copy of the database, before any further attempts can be made. We anticipate receiving this during the course of the week.

“The overall impact on Operation Perth remains under assessment and we will be in a better position to provide a fuller update once the outstanding analysis and recovery work has been completed.

“I appreciate that this update may cause concern for families, and I would encourage anyone with questions or concerns to contact Operation Perth, where the team will be happy to provide support and, where possible, further information.”

Maternity services at NUH were under the spotlight again following the landmark review, published in June, that found more than 500 mothers and babies suffered potentially avoidable harm or died due to “deeply embedded systemic failures”.

Officials at NUH said the latest error occurred while a copy of a radiotherapy database was being created.

A setting that should have been changed, before a set of pre-written computer instructions was run, was “missed” and the process was carried out on a maternity database instead, causing records to be overwritten.

The trust has restored clinical information, including notes, observations and test results, but has been unable to restore a complete history of who viewed records.

It means “in most cases”, the trust may be unable to confirm whether a maternity record was viewed by a particular person between September 2011 and November 2022.

Information about current maternity patients has not been affected and no patient information was “accessed or used inappropriately” after the incident, NUH added.

The trust said the Information Commissioner’s Office (ICO) was notified and that it had taken steps to improve its technical processes to prevent a similar incident.

Andy Callow, chief digital and information officer at NUH, said: “I am sorry for the concern and distress this incident may cause to women and families affected.

“On 18 August 2026, a human error during a routine technical process resulted in a maternity records database being unintentionally overwritten. We took immediate action to investigate the incident and recover the affected information.”

A statement from the Nottingham Maternity Family Group – which represents many of those affected by the wider scandal – said the incident was “extremely unnerving”.

“Families who have already endured preventable harm, injury and bereavement should not also have to worry about the security of the records of their experiences,” it said.

“The ability to trust NHS professionals to look after both patients and their data is paramount, but far too many Nottingham families feel that the NUH has fallen short of this.

“With each new incident, the trauma of what we have faced is compounded and the confidence and trust we have in the trust is further eroded.”

The group added it was pleased the ICO and police were investigating the latest data loss to see whether any criminal offences may have occurred, why the data was deleted and whether patients’ rights and privacy were unlawfully compromised.

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