Professor Sir Richard Doll, chairman of the study group said the findings should reassure parents.

BBC: Radon cancer fears dismissed

The research, published in the British Medical Journal, was led by the eminent cancer expert Professor Sir Richard Doll, of Oxford University.

BBC: Smoking 'does not prevent Alzheimer's'

So the UK Childhood Cancer Survey, headed by Sir Richard Doll, effectively debunks the Bristol team's work - or at least as far as the UK is concerned.

BBC: Battle lines drawn in pylon debate

Further, Sir Richard Doll, who first brought our attention to the links between smoking and lung cancer said: "I do not mind people smoking in my presence, since the risk of harm is so minimal".

BBC: Non-smoker