Blood stocks have been boosted by 30 per cent in preparation for the Olympics, NHS Blood and Transplant has said.
Following a campaign to increase blood supplies in time for the Games, 468,000 people donated blood, an NHSBT spokesman said.
Demand for blood is likely to soar during the London 2012 Games as millions of additional people descend on the capital.
Requests from hospitals have already begun to rise, the spokesman said.
But the NHSBT said there could be a fall in blood donations during the celebrations when donors’ routines are disrupted.
The spokesman cautioned that a drop in donations during the start of the Olympics could have an impact on stocks for September, when the Paralympics will be under way, since blood has only a 35-day shelf life.
NHSBT spokesman Jon Latham said: “We want to say a huge thank you to all the donors who helped us hit an ambitious target to help the nation prepare responsibly for the Games.
“We do need to maintain this higher level of stock right through to September and have already started to see appointment calls drop off as the celebrations begin, so please do keep donating throughout August to help see us through to the end of the Paralympics in September.”