The aftermath of the "major" cyber attack which has hit the NHS is likely to last for a number of days, experts have said.
A total of 48 NHS trusts in England and 13 NHS health boards in Scotland were crippled in the global attack on Friday when a ransomware virus infiltrated dozens of NHS organisations.
Five NHS England trusts were still not back to normal on Saturday, despite NHS Digital engineers working "around the clock" in a bid to fix the problem.
NHS Digital continued that fewer than five per cent of devices within the health service still use the old Windows XP system.
"We are aware of widespread speculation about the use of Microsoft Windows XP by NHS organisations, who commission IT systems locally depending on population need.
"While the vast majority are running contemporary systems, we can confirm that the number of devices within the NHS that reportedly use XP has fallen to 4.7%, with this figure continuing to decrease.
"This may be because some expensive hardware (such as MRI scanners) cannot be updated immediately, and in such instances organisations will take steps to mitigate any risk, such as by isolating the device from the main network."
The Home Secretary has revealed that 48 of the 248 NHS trusts in England have been hit during a "major" cyber attack.
A further 13 NHS Health Boards in Scotland were also targeted in the attack.
Speaking after chairing an emergency Cobra meeting, Amber Rudd added that all but five NHS England trusts are now back to normal, praising the "good work" and "resilience" of NHS staff in making this happen.
Asked if Health Secretary Jeremy Hunt would be making a statement on the attack, the 53-year-old that "plenty of NHS representatives" already had done and were due to.
Amid suggestions outdated software left some health service systems vulnerable after a security package was stopped in 2015, Ms Rudd said it is important to remember that it was not just the NHS which had been affected.
"If you look at who's been impacted by this virus, it's a huge variety across different industries and across international governments.
"This is a virus that attacked Windows platforms. The fact is the NHS has fallen victim to this.
"I don't think it's to do with that preparedness. There's always more we can all do to make sure we're secure against viruses, but I think there have already been good preparations in place by the NHS to make sure they were ready for this sort of attack."
Government bodies and other organisations could also be affected by the malware attack that brought down some NHS services, a cyber security expert has warned.
Companies operating large networks, thought to be particularly vulnerable, are being urged to make sure they are secure in the wake of the attack.
"Absolutely it's highly possible that as the days come forward unfortunately we are going to hear that more organisations and government bodies are going to have been affected," cyber security expert Paul Norris said.
"Unfortunately, it's going to be big names and it's going to be organisations that have got weakened security controls that are going to be mostly impacted by this."
A cyber attack on the NHS has exposed the "vulnerability" of the public sector and society in general to harmful malware, according to Nicola Sturgeon.
The SNP leader revealed that 13 health wards in Scotland were among the services affected by the attack on Friday, which targeted 40 NHS Trusts, Nissan's UK plant in Sunderland and a further 90 countries worldwide.
Mrs Sturgeon insisted that no patient data had been compromised by the ransomware "in any way".
"I think it is hugely concerning and I think this underlines the vulnerability of not just the public sector but society generally to cyber attacks," she said.
"It also underlines the importance of all organisations making sure that they have all appropriate measures in place to protect against those kind of attacks."
Nissan's UK plant in Sunderland has been hit by a "major" cyber attack which also struck the NHS.
The car manufacturing firm announced on Saturday that the ransomware assault had affected "some" of its systems at the Tyne and Wear hub.
The Newcastle Evening Chronicle reported that the plant's systems were first affected on Friday night, briefly halting production.
A statement from a Nissan spokesperson said: "Like many organisations, our UK plant was subject to a ransomware attack affecting some of our systems on Friday evening.
"Our teams are working to resolve the issue.”
Jeremy Corbyn has "nothing but contempt" for the perpetrators behind the NHS cyber attack.
The Labour leader let rip against the purported attackers, who launched the ransomware assault against at least 70 different countries, as "unbelievably disgusting".
So far some 40 NHS Trusts have been affected, resulting in a major incident being declared.
"What we've now got is a bunch of 21st Century highway robbers that have hacked into our NHS and are basically offering protection money to get the information back in order to treat cancer patients or anybody else," Mr Corbyn said.
"It's unbelievably disgusting and I've got nothing but contempt for those people that have done it, and I'm sure all of you would share that."
Mr Corbyn was also critical that there had not been a renewal of certain NHS protection systems since 2014, leaving them "not upgraded and not protected".
The home secretary said that 45 parts of the health service had been affected by the malware attack, but that patient data appears secure.Read the full story ›
After spotting a domain name hidden in the malware code one researcher halted the spread of a bug that has hit more than 70 countries.Read the full story ›
Russia's interior ministry has said it has also come under cyber attack.
No further details were immediately available.
More than 70 countries appears to have been affected by cyber attacks, two security companies have said, with Russia said to be the hardest hit.
The malware used in the attack is thought to have been based on an NSA-developed programme that was made public by hackers last year.Read the full story ›