Ten years of using a mobile phone results in no increased risk of a tumour in the nerve connecting the ear to the brain, researchers said on Tuesday.

But amid public concern about a possible link, the scientists who conducted the largest study so far on the subject said they could not rule out a higher risk over a longer period.

“The results of our study suggest there is no substantial risk in the first decade after starting use,” said Anthony Swerdlow of the Institute of Cancer Research. “Whether there are longer-term risks remains unknown, reflecting the fact that this is a relatively recent technology.”

The study, published in the British Journal of Cancer, focused on the risk of acoustic neuroma, benign tumours that grow in the nerve connecting the ear and inner ear to the brain, close to where handsets are held.

Research has also investigated the possible association of other kinds of brain tumour with mobile phones, but scientists say acoustic neuroma would be a prime candidate to be affected.

Previous independent studies have found mobile phone radiation may have some effect on the human body, such as heating up the brain and causing headaches and nausea.

But no study that could be independently repeated has proved mobile phones have permanent harmful effects and the mobile phone industry argues there is no conclusive evidence that electromagnetic radiation causes harm.

About 780 million mobile phones are expected to be sold this year, and nearly 2 billion people around the world use one.

The institute’s analysis pooled studies conducted in Britain, Denmark, Finland, Norway and Sweden - all countries where mobile phones were introduced early.

Cancer charities welcomed the findings.

“However, it’s important researchers continue to monitor phone users over coming years as mobiles are still a relatively new invention,” said Cancer Research UK’s Julie Sharp.