Hospitals across Britain today cancelled appointments and turned away patients after a large-scale cyber attack by a suspected 'ransomware' crippled major IT systems at the health facilities.

A number of hospitals across 16 trusts in London, Blackburn, Nottingham, Cumbria and Hertfordshire have been affected, resulting in many doctors resorting to pen and paper as phone and IT systems were shut down.

Following the cyber attack, the hospitals cancelled appointments and turned away patients, asking them to come only if it was an emergency. National Health Service England said they are 'aware of the issue and are looking into it'.

Among those affected is the East and North Hertfordshire NHS Trust, which said it is experiencing problems with computers and phone systems.

It has postponed all non-urgent activity today and is asking people not to come to A&E at the Lister Hospital in Stevenage.

'A number of NHS organisations have reported to NHS Digital that they have been affected by a ransomware attack,' the public health service said in a statement.

IT specialists are working to resolve the problem as quickly as possible.

An NHS Digital statement said: "NHS Digital is working closely with the National Cyber Security Centre, the Department of Health and NHS England to support affected organisations and ensure patient safety is protected."

"Our focus is on supporting organisations to manage the incident swiftly and decisively, but we will continue to communicate with NHS colleagues and will share more information as it becomes available," it said.  -- PTI