A study by an award-winning cancer expert shows that cell phone use could kill more people than smoking, it is reported.

According to the U.K.'s Independent newspaper, the study, headed by Dr. Vini Khurana, shows that there is a growing body of evidence that using handsets for 10 years or more can double the risk of brain cancer.

Khurana — one of the world's top neurosurgeons — based his assessment on the fact that three billion people now use the phones worldwide. That is three times higher than people who smoke. Smoking kills some five million globally each year.

He warned that people should avoid using handsets whenever possible and called on the phone industry to make them safer. France and Germany have already warned against the use of mobile phones, especially by children, it is reported.

The study is said to be the most damning indictment of cell phone use. According to the Independent, cancers take at least 10 years to develop, which has influenced earlier cancer studies showing relative safety when using cell phones.