By ROB COOPER
Grim: The group walk through central London wearing only skin-coloured underwear and sandals as an inch and a half of rain fell
It probably seemed like a bright idea at the time.
These campaigners launched a blood donor appeal ahead of the Olympics to get people to help replenish supplies - but they seemed to have forgotten about the weather.
Wearing only skin-coloured underwear and sandals, the group were forced to brave the damp as an inch and a half of rain fell in central London.
They were showing off their 'body art-ery' to raise awareness of the need for people to donate now. Britain's blood stocks need to rise 30 per cent above normal levels in time for the Queen's Jubilee and the Olympic Games this summer, according to the NHS. The group walked around London's St Pancras Station but dared not venture outside without umbrellas.
The NHS has warned that regular donors miss appointments more regularly when large public events take place because they are out of their normal routine or away.
Campaign: Bethany Holman-Brooks, 14, is pictured centre. She regularly receives blood as she is being treated for lymphoblastic leukaemia
Brave: The group of eight campaigners walk through St Pancras station in London yesterday as temperatures fell
An influx of foreign visitors in London will also increase medical need and may place pressure on certain blood groups that are more common in other countries.
Britons with O positive and O negative blood types are particularly in demand, with additional appointments being created and some facilities extending opening hours to give donors more flexibility.
First-time donors are also being encouraged to give blood to cope with the demand.
One problem for the health service is that blood decomposes very quickly, with red blood cells and plasma lasting just 35 and seven days respectively.
Blood stock fears: The NHS say they will need 30 per cent more donors now because the number of people donating will fall during the Olympic Games and around the Diamond Jubilee
As a result, supplies have to be replenished frequently to ensure a steady flow for medical use.
Hospitals in England and North Wales need 7,000 units of blood every day and each unit saves or improves the lives of three patients.
Jon Latham, spokesman for NHS Blood and Transplant, said: 'This year we have a unique situation and need the public's help to counterbalance the inevitable dip in donations as people celebrate a memorable summer for the country. We need to adjust the mix of stocks so we are well prepared as a responsible host for these exciting events.'
Supply fears: Hospitals in England and North Wales need 7,000 units of blood every day and each unit saves or improves the lives of three patients