Health service IT systems are back online following Friday’s global outage, according to NHS England. However, it has warned that there may still be disruption, particularly with GP services who may need time to rebook appointments. The problems with faulty security software affected more than eight million computers worldwide, bringing chaos to transport networks and health services.

Experts have warned that the process of fixing all the computers will continue into the coming week. The NHS asked patients with appointments this week to attend as normal unless told otherwise. "Thanks to the hard work of NHS staff throughout this incident we are hoping to keep further disruption to a minimum, however there still may be some delays as services recover, particularly with GPs needing to rebook appointments, so please bear with us," spokesperson said.

On Sunday, the British Medical Association, which represents doctors, said GPs had been "pulling out all the stops" but would need time to catch up with lost work. The IT outage affected the EMIS platform, which many GPs use to manage appointment bookings and patient records - including sending prescriptions to pharmacies. The BMA said Friday had been "one of the toughest single days in recent times for GPs across England".

"Without a clinical IT system many were forced to return to pen and paper to be able to serve their patients." Friday's outage was caused by a faulty update to CrowdStrike antivirus software, which crashed Micro.