The London Olympics pose a severe risk to Britain’s vital blood supply, experts warn.

New NHS research has revealed that major sporting events coincide with a sharp drop in blood donations, leading to fears of a ‘perfect storm’ when the extra demand for blood created by tourists visiting the Olympics are added to the effect it could have on supplies.

NHS Blood and Transport bosses have recruited Olympians – including Bath ice queen Amy Williams – to give blood donations next year an early push start.

Statistics show that 93 per cent of donors give blood during the working week, and when there are big sporting events or a string of bank holidays national donation levels drop.

In the South West alone:

The bumper bank holidays around Easter and the Royal Wedding week resulted in 3,500 fewer donations.

In 2010 on one day alone there were 851 fewer donations than the previous year due to the combination of particularly sunny weather, the World Cup quarter final and Andy Murray’s Wimbledon semi final.

Jonathan Sewell, NHSBT register development manager for the South West, said: “2012 is going to be an exciting year for the UK but we’re concerned that the cluster of major events could dramatically impact the number of blood donations coming in.

“Approximately two million units of blood will be needed by hospitals throughout 2012, and the equivalent of 500 extra donations will be needed each week in the first six months to help us build blood stocks and cover extra potential need from Olympic visitors. We’re calling on the public to make regular blood donation a New Year’s resolution.”

A significant drop in donations could have a massive impact on the thousands of people in England who require blood. Blood ‘products’ are not just for road traffic accidents, they are used to treat people with cancer, sickle cell disease, for new mums and babies, and during surgery.

Olympic bob skeleton gold medalist Amy Williams is a registered blood donor. Amy said: “I have been a registered donor for some time now, but my hectic training schedule means I haven’t been able to give blood lately.

"If there is one New Year’s resolution I’d like to make and keep for 2012, it’s to donate blood. I urge anyone who can give blood to do so. Giving blood is so important – not only is it quick and simple, but it saves lives.”

Visit www.blood.co.uk to register and find the nearest donation centre.