Health officials have launched an urgent appeal for people with two blood types to donate amid fears stocks will run dry in two days.
NHS Blood and Transplant today admitted it is running desperately low on supplies of O negative and B negative blood in the UK.
It blamed low donations over the bank holiday weekend, as many chose to bask outdoors in the sizzling 86°F (30°C) temperatures instead.
O negative is the ‘universal’ blood group and is often used when a patient’s blood type is unknown, such as in emergency situations.
NHS Blood and Transplant today admitted it is running desperately low on supplies of O negative and B negative blood in the UK
However, extra pressure is being put on this blood type because it is being used as a substitute for dwindling supplies of Ro blood.
The rare subtype, most common in black people, was the subject of a 75 per cent surge in demand between 2014 and 2016.
The majority of this is used to treat sickle cell disease – a condition particularly common in those of an African or Caribbean background.
But at present, just one per cent of all blood donations in the country are made by black people, statistics show.
B negative stocks are also low also because many patients with serious blood disorders, like sickle cell, need this blood type.
Only 2 per cent of donors are B negative, which is also a blood group more common in black people.
People with sickle cell disease have abnormal red blood cells which do not move around blood vessels easily and carry less oxygen around the body.
The condition, which affects around 15,000 people in the UK, can be extremely painful and cause life-threatening infections. Blood transfusions can help prevent or relieve these symptoms.
Mike Stredder, director of blood donation at NHSBT, said: ‘The overall demand for blood is declining year on year.
‘However, the need for specific blood groups such as Ro blood type and O negative are on the increase.
‘We need an additional 4,000 regular O negative donors to those we have now to consistently provide seriously ill patients with the blood they need.
‘If you know you are O negative or B negative and have never donated before, now is the time to make a difference.’
NHSBT needs to collect 1.5 million units of blood each year to meet the needs of patients across England.