The largest group of international experts assembled to consider the controversy over breast screening has concluded that it does save lives.

But there was no clear evidence that self examination had any impact on mortality from the disease.

The group of 24 experts from 11 countries concluded that deaths from breast cancer were reduced by 35 per cent among women aged 50–69 who attended regularly for screening, equivalent to one life saved from breast cancer for every 500 women screened.

The group, brought together by the International Agency for Research on Cancer (IARC) of the World Health Organisation (WHO) spent eight days earlier this month at the agency's headquarters in Lyon, France, considering the evidence on breast screening.

Their statement backing screening, released yesterday, will provide crucial support to the beleaguered NHS breast screening programme.

Julietta Patnick, co-ordinator of the NHS programme, said: "I am very pleased. I think this is the definitive answer. We offer breast screening on the basis of informed choice for women but in the context of a national policy to promote breast screening the finding that is is successful is reassuring."

Mrs Patnick said the screening system had been "under siege" for the last two years since two Danish researchers published a paper in The Lancet casting doubt on its value and arguing that many of the studies claiming to show a benefit were scientifically flawed. The number of women attending screening had declined since, she said.

In their statement yesterday, the IARC group of experts said the criticisms of the studies were "unsubstantiated" and that remaining deficiencies "were judged not to invalidate the trials' findings".

The lack of evidence that self examination helps to save lives is a blow to hopes that it would help protect women who had no access to screening.

Professor Bruce Armstrong of IARC said a trial in Shanghai showed no difference to the death rate from breast cancer.

He said: "There is insufficient evidence to make a decision about whether breast self examination can save lives. But if a woman notices a change in her breast she should seek a medical opinion."