Londoners are urged to register as donors during National Blood Week.
NHS Blood and Transplant need 200,000 new donors a year and there is a particular need for young people and black people to donate.
Half of donors in England are over 45 so it is important to recruit younger people to meet patient needs now and in the future.
Sickle cell disease is the fastest growing genetic condition in England and most common in black people, causing extreme pain and life-threatening infection.
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