Health officials have launched an urgent plea for more black people to give blood.
NHS Blood and Transplant (NHSBT) said that 40,000 more donors were needed to meet growing demand for Ro blood, a subtype that is more common among black people.
The authority said that there was a 75% increase in the amount of Ro blood issued to hospitals in England between 2014 and 2016.
Much of the blood is used to treat sickle cell disease, a condition particularly common in people of African or Caribbean descent.
People with sickle cell disease have abnormal red blood cells that do not move around vessels easily and have a reduced capacity for carrying oxygen around the body.
The condition, which affects around 15,000 people in the UK, can be extremely painful and cause life-threatening infections and other complications such as stroke and loss of vision. Blood transfusions can help prevent or relieve these symptoms.
To get the best treatment, patients need blood that is closely matched, which is most likely to come from someone of the same ethnicity, but NHSBT said that only 1% of people who give blood in England are black.