Staff returned to work today following the ransomware attack last week.

Cyber security experts have warned that the ransomware virus, which affected one in five NHS Trusts, could be reactivated by computers and devices that have not yet been switched on.

On Sunday evening seven acute hospital Trusts continued to experience major disruption and were diverting patients away from A&E for a third consecutive day.

In total 47 organisations reported being affected by the cyberattack and the disruption will continue into the new working week.

NHS regional director for London, Anne Rainsberry, told Sky News: “If you have not heard from your hospital and you have an appointment, our message is you should attend as normal.”

But she warned patients: “It may be a little bit slower when you get there because hospitals are using different systems, so please be patient.”