THE NHS is urging people to continue donating blood following a cyber attack that brought operations to a halt at major hospitals in London.
The cyber gang took control of the IT network, crippling services such as diagnostic blood testing.
Brits with O blood type are being urged to book appointments to donate.
O blood-type is important because it is 'universal' - regardless of a person's blood type, they can recieve a tranfusion with O blood in most cases.
Given the IT attack has prevented affected hospitals from matching patients’ blood at the same frequency as usual, O-blood type is in need more than ever before.
Spectacular New Year fireworks light up London sky as huge crowds celebrate across UK for first time in three years
It comes after several London hospitals declared a critical incident, cancelled operations and tests, and were unable to carry out blood transfusions this week after the attack on the pathology firm Synnovis.
Qilin, a Russian group of cyber criminals, is understood to have been behind the attack, which impacted King's College Hospital, Guy's and St Thomas', the Royal Brompton and the Evelina London Children's Hospital, and primary care services.
O BLOOD NEEDED
NHS Blood and Transplant is now calling for all O-Positive and O-Negative donors to book appointments in one of London's 25 NHS donor centres to boost stocks.
The NHS said hospitals need to use O-type blood for surgeries and procedures requiring blood.
Blood has a shelf life of 35 days, so stocks need to be continually replenished.
To support London hospitals in carrying out more surgeries and to provide the best care we can for all patients, we need more O-negative and O-positive donors than usual.
Dr Gail Miflin
That means more units of these types of blood than usual will be required over the coming weeks.
Also, stocks are low following both May's bank holidays and the recent half-term.
O-negative is the type that can be given to anyone and is used in emergencies or when a patient's blood type is unknown.
Air ambulances and emergency response vehicles carry O-negative supplies.
Robbie Williams poised to launch his own brand of energy drinks to rival Prime
Just eight per cent of the population have type O Negative, but it makes up for around 15 per cent of hospital orders.
O positive is the most common blood type; 35 per cent of donors have it, and it can be given to anybody with any positive blood type.
This means three in every four people, or 76 per cent of the population, can benefit from an O-positive donation.
'BOOK AN URGENT APPOINTMENT'
Dr Gail Miflin, NHS Blood and Transplant chief medical officer, said: "To support London hospitals in carrying out more surgeries and to provide the best care we can for all patients, we need more O-negative and O-positive donors than usual.
"Please book an urgent appointment to give blood at one of our 25 town and city donor centres, which currently have good appointment availability.
"We have availability for donors who know they are type O, but we also welcome new donors who don't yet know their blood type.
"You might have one of these special types that can be used in emergencies."
Professor Stephen Powis, medical director for NHS England, said: "NHS staff are continuing to go above and beyond to minimise the significant disruption to patients following the ransomware cyber attack on Synnovis earlier this week.
"Urgent and emergency services are available as usual, so patients should access services in the normal way by dialling 999 in an emergency and otherwise using NHS 111 through the NHS App, online, or on the phone.
"But unfortunately, we know that several operations and appointments have been postponed or diverted to other neighbouring hospitals not impacted by the cyber-attack, as we prioritise pathology services for the most clinically urgent cases.
"To help London staff support and treat more patients, they need access to O-Negative and O-Positive blood, so if one of these is your blood type, please come forward to one of the 13,000 appointments currently available in NHS Blood Donor Centres."
For more information or to make an appointment to donate your blood at the nearest centre, click here.