A leading Chinese advocate of internet freedoms has issued a scathing denunciation of the US portal Yahoo for its role in helping Communist authorities to prosecute an independent-minded local journalist, jailed for 10 years for “leaking state secrets”.

Veteran dissident Liu Xiaobo, in an open letter to Yahoo co-founder Jerry Yang, accuses the US company of betraying its customers and supporting dictatorship by providing information on journalist Shi Tao to Chinese authorities.