Living near a high-voltage power line roughly doubles the risk of childhood cancers such as leukaemia, UK scientists say.

Dr Gerald Draper of the Oxford-based Childhood Cancer Research Group, said a recent study he led studied 35,000 cases of childhood leukaemia and other cancers between 1962 and 1995, and results suggest a slightly higher chance of developing the disease among children living within 100 metres of a high-tension overhead cable.

But he angrily denied claims that the work had been suppressed by himself or the Department of Health, which commissioned it. He also emphasised yesterday that the link to childhood cancers was weak.

An independent group, the Trentham Environmental Action Campaign, estimated the power-line effect would cause between two and six of the 500-odd cases of child leukaemia reported each year in Britain. On average, one in 2,000 children under 15 develops leukaemia, and there are 1,500 childhood cancers each year.

Some international studies have shown children exposed to the highest electromagnetic fields (EMF) in the home - above a value of .4 microtesla, as it often is in houses below power lines - are twice as likely to suffer leukaemia as children exposed to low EMF. About .5 per cent of the UK population lives in houses above that level, says the National Radiological Protection Board, which advises the Government on hazards from radiation.

Maureen Asbury, president of the Trentham campaign, said: "The Government should act now. We aren't prepared to wait 10 years while they dither. First, ministers should legislate against building houses near power lines. Then they should set up a project to remove the lines that traverse homes. We know it can't be done immediately, but it needs to be started."

But Dr Draper dismissed claims made on Sky News that he or the Department of Health had tried to keep the findings secret.

"We hope to submit our paper, which is now complete, to a journal in about a fortnight for publication," he said. "But it is untrue to say the DoH is suppressing this work: it has been among those pressing me to get it published. "Second, even if it wanted to suppress them, my contract allows me to publish what I want. And these days, researchers are keen to publish work: that's how you justify your salary."

Sky News had claimed the results of the study had been kept under wraps for three years, after being presented in 2001. Dr Draper said that in 2001 he had had no results to discuss.

"About 18 months ago, I ran a private workshop with other scientists to talk about my preliminary findings, which were fuzzy; I didn't understand them fully myself and wanted to see if there were other explanations. There are geographic variations, and class variations, in the incidence."

He rechecked the calculations to produce the final report, which was drafted over the summer. The study does not find the biological mechanism by which power lines might increase the risk of cancers. That remains a mystery.