Mobile phone use does not lead to a greater risk of brain tumour, the largest study on the issue has said.
Children are still advised not to use mobile phones unless necessary
The study of 2,782 people across the UK found no link between the risk of glioma - the most common type of brain tumour - and length of mobile use.
Among cancer sufferers the tumours were more likely to be reported on the side of the head where they held the phone.
But the British Medical Journal study said people over-reported phone use on the side their cancer developed.
The research, which was carried out by the British arm of an international project called Interphone, reiterates the findings of most earlier studies in saying that there is no connection between cancer and mobile phone use.
The team of researchers, involving scientists from Leeds University, the Institute of Cancer Research and the University of Nottingham, spoke to 966 people diagnosed with glioma and 1,716 without the condition in five areas of the UK.
All 2,783 were interviewed about their history of mobile phone use over the previous 10 years.
They were asked to recall in detail how much they used their mobile phones, how often they used hands-free kits and what types of phones they had used.
Research author Professor Patricia McKinney, Professor of Paediatric Epidemiology at the Leeds University, said: "For regular mobile phone users, there was no increased risk of developing a glioma associated with mobile phone use."
She acknowledged that there appeared to be an increased risk among brain cancer sufferers on the side of the head where they held the phone.
MOBILE PHONE FACTS
Available in the UK since 1985
Widely used since late 1990s
Now estimated to be owned by more than 40m Britons, including many children
Most studies have found no raised risk of brain tumour
But long-term effects still not known
Children still advised to use mobiles only when necessary
The team, however, did not put this down to a causal link, because almost exactly the same decreased risk was seen on the other side of the head, leaving no overall increase risk of tumours for mobile phone users.
Instead, they blamed biased reporting from brain tumour sufferers who knew what side of the head their tumours were on.
Another research team member, Professor Anthony Swerdlow of the Institute of Cancer Research, said: "It would be very misleading to the public to say that because there was a positive that this (mobile phones) causes brain tumours."
He explained: "If we had found a raised risk overall and it was all coming from one side, I would believe there was a real case.
"But as there is a drop on the opposing side - the overall risk is not raised.
"That makes it rather unlikely that there is a raised risk."
But he added that epidemiological studies could never show there was no risk of an activity, they could only suggest there was no raised risk.
The Health Protection Agency said the research was good news, but that it did not give mobile phones a clean bill of health.
The board said it would not be changing its advice that children should not make unnecessary mobile phone calls.
Dr Kat Arney, science information officer at Cancer Research UK, said research such as this was vital for getting to the environmental causes of cancer.
"This is the biggest and most thorough study into mobile phones and glioma so far, and it adds to the growing evidence that there is no link.
"Although we still don't know about the very long-term effects of phone use, these results are reassuring for everyone with a mobile."
Wendy Fulcher, who founded ther Brain Tumour Research Campaign, said she hoped people would be finally reassured by the results of the research.
She added: "In relation to other cancers, brain tumours are the poor relation when it comes to research funding.
"There should be more money focused on the root causes of brain tumours."
Alasdair Philips, director of campaign group Powerwatch, says the study "doesn't really prove anything".
"I think they should have waited another couple of years and recruited more people with brain tumours so they could have interviewed them, because the trouble was they went back a few years and the people had died.
"If you get a grade four glioma you can die within a year or 18 months of it being diagnosed, and these people are just gone, so they couldn't get their mobile phone history."