Health officials are urging more black people to give blood, to meet a growing demand for a special subtype of blood.
NHS Blood and Transplant (NHSBT) said that 40,000 more black donors are needed, after the amount of Ro blood issued to hospitals in England rose by 75% between 2014 and 2016.
Ro blood is more common in people with an African or Caribbean family background.
A high proportion of Ro blood, which is a subtype of the Rhesus blood group, is used to treat sickle cell disease.
The condition, which affects around 15,000 people in the UK, is particularly common in black people.
Sickle cell disease can be extremely painful and sufferers are at higher risk of developing life-threatening conditions, having strokes and losing their vision.
But blood transfusions can relieve or prevent these symptoms.
To ensure patients receive the best treatment, blood matches must be as close as possible.
This means blood from someone of the same ethnicity is more likely to produce a better outcome.
But NHSBT said just 1% of people who give blood in England are black.
To mark National Blood Week, NHSBT has launched a new campaign – £ImThere – to try to encourage more donors to register and donate.
Mike Stredder, director of blood donation, NHS Blood and Transplant, said: ‘We need to ensure that we have the right mix of donors and blood types, to help meet the needs of all patients who need life-saving treatment, especially those with conditions like sickle cell disease who require blood which is more closely matched than by group alone.
‘In recent weeks, we have been overwhelmed by the numbers of people stepping forward and wanting to donate and show their support for those affected by recent tragic events.
‘Thankfully, due to the loyalty of our regular donors, our emergency stocks have proven to be strong and sufficient, but we still need to ensure that we can be there every day, for every patient who needs us.’