An urgent call has gone out to medical students to help London hospitals recover from a major cyber-attack.

A critical incident was declared on Tuesday after the ransomware attack targeted the services provided by pathology firm Synnovis.

Services including blood transfusions and test results have been severely disrupted.

In a leaked message to staff at Guy’s and St Thomas’ Trust, trainee medics have been asked to volunteer for 10 or 12-hour shifts.

A spokesperson for NHS London said staff were “working around the clock” to minimise “the significant disruption to patient care”.

The cyber-attack, believed to have been carried out by a Russian group calling themselves Qilin, affected services provided by King’s College Hospital NHS Foundation Trust as well as Guy’s and St Thomas’ NHS Foundation Trust.

Surgery and transplant operations at Royal Brompton and Harefield hospitals are believed to have been impacted, as is the Evelina London Children’s Hospital and primary care services.

It is understood staff on wards are now using paper-based methods and signing blood transfusion bags.

In the message to trainees, which has been seen by the BBC and The Sunday Times, medical students were told they would act as “floorwalkers” and hand deliver blood tests.

It said: “In this critical situation, we urgently need volunteers to step forward and support our pathology services.

“The ripple effect of this extremely serious incident is felt across various hospital, community and mental health services in our region.”

Students were told that their assistance was “crucial” and that it was an opportunity to “demonstrate your commitment to patient care”.

In a separate leaked email to staff, the chief executive at Guy’s and Thomas’ Trust, Prof Ian Abbs, said difficult conversations were being had with patients who have had appointments cancelled.

He confirmed the disruption would last for a number of weeks and that a response was being coordinated by the regional NHS England team.

At Guy’s and St Thomas’, trust staff raised concerns that clinical decisions were being made without the support of pathology.

In another letter they were told staff had the full support of management “to make decisions based on your best professional judgment”.

A spokesperson for NHS London said they were sorry to all those impacted by the cyber-attack.

“Pathology services are integral to a wide range of treatments and we know that a number of operations and appointments have been cancelled due to this attack,” they said.

“We are still working with hospitals and local GP services to fully assess the disruption, and ensure the data is accurate.

“In the meantime our advice to patients remains, if you have not been contacted please do continue to attend your appointments.”

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