Dr Jonathon Tyrer who also worked on the project comments: "The IBIS risk evaluator brings together everything we know about the causes of breast cancer to predict a woman's individual risk. We believe it will help doctors to deal with the growing number of the 'worried well' who visit their GP seeking advice on how they can avoid illness."

The program was originally devised to help find high-risk women who could take part in Cancer Research UK's breast cancer prevention trial, IBIS II*(2). However, the researchers quickly realised that the program had much wider potential.

Professor Cuzick explains: "We hope to develop this tool further to include risk factors for a variety of common diseases including heart disease and other cancers.

"One day it might be available in every GP surgery, perhaps even in every shopping centre, so people can find out their personal risk of various diseases and get a print out of what they can do to reduce their risk."

Cancer Research UK's Director of Clinical and External Affairs, Professor Robert Souhami, says: "There is no single cause of breast cancer but through research we have been able to find some of the most important risk factors.

"This program is a useful tool because it takes all the known risk factors into account and gives us an idea of who is most at risk. Knowing who is at risk is the first step towards preventing breast cancer."