Patients have told how hospitals descended into “pandemonium” and “chaos” as medical staff lost track of blood tests and drugs when the cyberattack hit.

Richard Waring told how doctors and nurses at Warrington Hospital were having to follow patients around, writing the results of vital tests on paper so they didn’t get mislaid, then making sure details were passed to the right medics.

He said the first blood tests he had done were lost so a second set had to be carried out.

preview image Video: ‘Saviour’ researcher: Cyberattack was amateur

Mr Waring, of Runcorn, Cheshire, managed to log his arrival with the hospital using the digitised system and said the situation was okay at first but described how it soon descended into “chaos”.

He said the hospital seemed to have no strategy in place for dealing with the breakdown of the computer system.

He told Sky News: “You could tell the nurses and doctors were doing the best they possibly could but they literally had no access to information. The information they had, had to be on paper and they had to make sure that was passed from one person to another.

“I mean in a digital era where information is instant, to have that taken away with no back-up or no strategy in place instantly… It was visible as a patient.”

:: Ransomware explained: Hacking for cash on rise

He said: “It was slightly concerning they couldn’t find prior records, certainly concerning the loss of bloods that was taken and I had to have bloods taken a second time.

“They were having to follow the bloods from one point to another and make sure they came back to the doctor and this was apparent with x-rays and other tests that they were doing with other patients.”

preview image Video: Cyberattack caused ‘pandemonium’ at hospital

Julie Maddison, who has a rare type of dwarfism, said York Hospital Accident and Emergency was gripped by “pandemonium” because of the speed at which the attack shut down patient records.

Ms Maddison, who is on controlled drugs, had been taken in by ambulance after becoming unable to move following surgery last week.

She says doctors lost her drugs and her records and in the end her family decided she would be better off at home so she discharged herself from the hospital.

She said: “I take quite a lot of medication and it is controlled drugs, and they didn’t even know where my controlled drugs were, which is frightening.

“I was absolutely terrified, not just for myself but what if somebody else had got hold of them… It could have killed them.”

She condemned the attackers as “despicable”, saying they “could have killed somebody” and that they should be “so ashamed of themselves”.

The malicious software behind the attack appeared to exploit a vulnerability in Microsoft Windows XP that was supposedly identified by the National Security Agency.

Home Secretary Amber Rudd said that hospitals had been told by Health Secretary Jeremy Hunt to update their computer systems and added it was “disappointing” this had not been done.

A statement from Warrington and Halton Hospitals Trust on Saturday morning said: “The Trust has back-up and support systems in place to ensure we can continue to function as normal – no surgeries have been cancelled and patients should attend as planned for their appointments and procedures.”

preview image Video: Biopsy patient not happy to be turned away

At the Royal London Hospital on Saturday morning, patients were being turned away.

One man told Sky News: “They wouldn’t let me in. They said it was actually patient safety and they locked some of the doors that led into the hospital so patients for outpatients or dermatology couldn’t even get in there.

“So I’ve just shrugged my shoulders. And I am lucky that what I have got is no terrible big deal but there was a lady standing next to me who came from Barts and been waiting a year. She’s less happy.”