Scientific evidence goes increasingly against the theory that mobile phones cause cancer, a new study has concluded.
The review carried out for the Institute of Cancer Research found "no convincing evidence of a link" between the technology and brain tumours.
The panel, set up by the International Commission on Non-Ionizing Radiation Protection, admitted however that the possibility of small or long-term repercussions could not be ruled out.
Their conclusions follow a wide-ranging study - the largest of its kind to date - which claimed that radiation associated with mobile handsets potentially increases the risk of glioma, a malignant form of the disease.
While the panel accepted the Interphone study findings were "comprehensive", they identified some problems with the study's design which made it difficult to draw definite conclusions.
The results, in conjunction with those revealed by a series of similar studies, showed no increases in brain tumours up to 20 years after the introduction of mobile phones, and a decade after their use became widespread.
Extensive research also failed to establish any biological explanation for how handsets could possibly cause cancer in humans while animals exposed to radiation appeared unaffected, they said.
However the group, led by the ICR's Professor Anthony Swerdlow, said uncertainty was bound to remain for years because research could not prove the complete absence of harmful side-effects.
"The results of Interphone and other epidemiological, biological and animal studies, and brain tumour incidence trends, suggest that within 10 to 15 years after first use of mobile phones, there is unlikely to be a material increase in the risk of brain tumours in adults," Swerdlow said.
"However, the possibility of a small or a longer term effect cannot be ruled out."
Examination of cancer rates during the next few years is expected to clarify the situation.
"If there are no apparent effects on trends in the next few years, after almost universal exposure to mobile phones in Western countries, it will become increasingly implausible that there is a material causal effect," he added.
"Conversely, if there are unexplained rising trends, there will be a case to answer."
David Spiegelhalter, Winton Professor of the public understanding of risk at the University of Cambridge, said: "This report is clear that any risk appears to be so small that it is very hard to detect - even in the masses of people now using mobile phones."
David Coggon, professor of occupational and environmental medicine at the University of Southampton, said the review was "carefully considered" and its conclusions "justified".
"Continued research is needed in case there are harmful effects in the longer term," he added, "but the news so far is good."
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