Does screening for breast cancer do more harm than good? Once, a question like that would have been dismissed as heretical nonsense. After all, according to the Government's official line, 1,400 lives a year are saved by screening. But over the past few years evidence has begun to be raised suggesting that the harm may outweigh the benefits. A "better safe than sorry" approach can lead to over-diagnosis and unnecessary mutilating surgery for a lesion that was not going to cause harm.

These claims are controversial. The current advice of the World Health Organisation is that breast screening saves lives and the benefits considerably outweigh the risks. Even so, the Government's leading cancer adviser, Sir Mike Richards, yesterday announced an independent inquiry into the issue after an eminent obstetrician, Professor Susan Bewley, dismissed the justification for the Government's current approach as "inadequate and unpersuasive". NHS leaflets on screening exaggerate the benefits and do not spell out the risks, she has complained.

So a new inquiry is to be welcomed. But it will be useful only if it is both truly independent and open-minded. Professor Richards, in an attempt to exclude those who have campaigned on the issue before, has said the inquiry should be conducted by researchers who have "never previously published on the topic of breast cancer screening". That is a sound instinct; in so doing, though, the inquiry must not thereby neglect the views and evidence of those who have most expertise.

Nor is Professor Richards himself beyond all controversy. Concern has been expressed that his track record places him firmly on one side of the debate. He has been accused of hiding behind experts rather than challenging them with due rigour. He is also involving Cancer Research UK which has a stated policy of trying to increase the numbers of women screened.

Whether or not a woman goes for screening is never a simple matter of choice. Advice is crucial, and women need the best informed, most balanced advice possible. That is what this new inquiry must offer.