The number of people giving blood dropped over the Jubilee weekend leading to national blood stocks falling by 7%, NHS Blood and Transplant (NHSBT) has warned.
National Blood Week kicks off on Monday and the NHSBT is urging the public to become donors and join the 4% of the population who currently give blood.
Past experience shows that even regular donors miss appointments during national events and celebrations as people become distracted and routines are disrupted - for example blood stocks fell by 20% during the 2006 World Cup.
This year NHSBT needs to build a 30% increase in blood stock levels ahead of the Olympics as the number of people donating during the Games is likely to plummet.
To promote this year's awareness campaign, Rosie Fortescue from Channel 4 reality show Made In Chelsea has rolled up her sleeves to recreate the Rosie the Riveter posters from the Second World War.
Miss Fortescue said: "This woman clearly knew how to get things done, and I feel honoured to become a modern day campaigner for the national blood stock build. Blood supplies are vital to the health service and every unit of blood can save or improve the lives of up to three people."
During the National Blood Week recruitment drive, additional appointments have been created and selected blood donor sessions have extended opening hours to give donors more flexibility to schedule a visit.
Regional recruitment events will also be driving awareness and enabling people to sign up.
NHSBT spokesman Jon Latham said: "We know from experience that major public events have a big impact on blood stocks so we prepared ahead for the Jubilee to build stocks in advance but we now need a huge effort from the public ahead of a summer of sport."
For more information about becoming a blood donor visit www.blood.co.uk or call 0300 123 23 23.