Suicidal people searching the internet are more likely to find advice on how to end life than sites offering help and support, a new study claims.

Researchers from the universities of Bristol, Oxford and Manchester performed searches likely to be undertaken by a person looking for instructions and information about methods of suicide using the four most popular search engines.

They came across 240 different sites, just under half of which provided some information about methods of suicide.

Almost a fifth of their hits (90) were for dedicated suicide sites and about half of these were judged to be encouraging, promoting or facilitating suicide.

Thirteen per cent of sites (62) focussed on suicide prevention or offered support and 12 per cent (59) actively discouraged suicide.

A fifth of support and prevention sites, 55 per cent of academic or policy sites and all news reports of suicides provided information about methods of suicide.

MSN brought up the highest number of prevention or support sites while Google and Yahoo retrieved the highest number of dedicated suicide sites.

Writing in the British Medical Journal (BMJ), the researchers say there is a need to strike a balance between freedom of expression and public protection but argue there are a number of ways to promote support sites.

"The differing content identified with the four search engines indicates that it is possible to influence what searches retrieve," they conclude.

"It may be more fruitful for service providers to pursue website optimisation strategies to maximise the likelihood that suicidal people access helpful rather than potentially harmful sites in times of crisis."