A report by the Institution of Electrical Engineers' health and safety committee said there was no evidence of a connection between low-frequency electro-magnetic fields and the disease.
Dr Tony Barker, medical physicist at the Royal Hallamshire Hospital, Sheffield, and chairman of the study committee, said: 'We can find no clear evidence to link low-level electro-magnetic fields with an increased risk of cancer.
'It is important to understand that showing an association between the two does not prove causation.
'Much of the concern has resulted from epidemiological studies which may establish such an association, but are not supported by any well-
accepted and replicated experiments. It is rather like finding circumstantial evidence without any forensic evidence to support it.'
The IEE review looked at 245 pieces of recently published work worldwide, but found no evidence to justify growing fears of possible harmful effects of such fields.
Dr Barker said calculations carried out by the team 'suggest that it would amount to one case of childhood leukaemia every five years in the whole of Sweden, which is not a very large figure.
'That figure, if translated in the UK, would be one additional childhood leukaemia death per year due to living under overhead power cables - that is, if it was true, and we don't believe it is proven.
'Approximately 200 children a year die in accidents in the home and about 5,000 people are killed on the roads every year.'
The reassurances are unlikely to silence environmental groups and people taking legal action over allegations of death due to power lines.