Patients are being warned that some planned appointments will be cancelled as The Royal London and Mile End hospitals aim to recover from Friday’s cyber attack.

Barts Health, which runs the hospitals, was among a fifth of the country’s NHS trusts to have its computers infected by ransomware.

A spokesman for the trust said: “Barts Health staff have been working tirelessly over the weekend, using tried and tested processes to keep patients safe and well cared for.

“However, our hospitals are still experiencing IT disruption and we are very sorry for any delays and cancellations that patients have experienced.

“As our hospitals are still experiencing some delays and disruption, we would ask the public to use other NHS services wherever possible.”

The trust will be reducing the amount of planned services across all its sites to ensure those it does run can be done so safely.

Some planned surgery and outpatient appointments will continue at all of the trust’s hospitals, including all renal dialysis services.

The spokesman explained that the trust has “slower than usual access” to its pathology and diagnostic services.

He added: “Where we need to cancel planned appointments, we will be contacting patients directly to make them aware and we apologise for any inconvenience caused.

“It is possible that we will not be able to contact all patients that we need to speak to, so we apologise if we are unable to proceed with your treatment once you arrive at hospital.

“We will prioritise clinically urgent planned appointments and our clinical teams are reviewing all our appointments to inform our decisions.”

Anyone who has a planned appointment and has not been contacted is advised to turn up as scheduled.

Dr Anne Rainsberry, NHS incident director, said: “We have been working with 47 organisations providing urgent and emergency care who have been infected to varying degrees.

“Most have found ways of working around this but seven, including Barts in London, have asked for extra support.”

The trust’s emergency departments are open today, and trauma and stroke care is also now fully operational.

GPs have also been asked to avoid requesting non-urgent tests and scans from the hospitals.