This study provides further firm evidence that exposure to the levels of magnetic fields found in the UK does not increase the risk of leukaemia, or other childhood cancer

Dr John Toy, Imperial Cancer Research Fund

Previous work in Bristol had suggested that power lines concentrate the levels of carcinogenic pollution in the atmosphere.

But Dr John Toy, medical director at the Imperial Cancer Research Fund, said he hoped the latest research would allay the fears of concerned parents living near electrical power lines, either overhead or underground.

"Childhood cancer is a very distressing disease and, despite the improving survival rates, it is imperative that we discover the root causes," he said.

"This study provides further firm evidence that exposure to the levels of magnetic fields found in the UK does not increase the risk of leukaemia, or other childhood cancer."

More than 400 children in the UK are diagnosed with leukaemia each year and around 300 with a brain tumour. However, new treatments mean that seven out of 10 children now survive cancer.