Using a mobile phone for more than 10 years increases the risk of getting brain cancer, according to the most comprehensive study of the risks yet published. The study - which contradicts official pronouncements that there is no danger of getting the disease - found that people who have had the phones for a decade or more are twice as likely to get a malignant tumour on the side of the brain where they hold the handset. The scientists who conducted the research say using a mobile for just an hour every working day during that period is enough to increase the risk - and that the international standard used to protect users from the radiation emitted is not safe" and "needs to be revised". They conclude that "caution is needed in the use of mobile phones" and believe children, who are especially vulnerable, should be discouraged from using them at all. Official assurances that the phones are safe have been based on research that has, at best, included only a few people who have been exposed to the radiation for long enough to get the disease, and are therefore of little or no value in assessing the real risk. The scientists pulled together the results of the 11 studies that have so far investigated the occurrence of tumours in people who have used phones for more than a decade, drawing on research in Sweden, Denmark Finland, Japan, Germany, the United States and Britain. They found almost all had discovered an increased risk, especially on the side of the head where people listened to their handsets. [One of the study's authors] said he uses a mobile phone as little as possible, and urges others to use hands-free equipment and make only short calls, reserving longer ones for landlines. He also said that mobiles should not be given to children, whose thinner skulls and developing nervous systems make them particularly vulnerable.