A Chinese court has sentenced a leading dissident to 11 years in jail for “inciting subversion of state power”, the clearest signal yet, according to analysts, foreign officials and human rights groups, that China has over the past two years reduced the already limited space for political dissent.

Although there were high hopes that events such as last year's Olympics in Beijing would encourage greater political openness in China, the unusually harsh sentence handed down to Liu Xiaobo on Christmas day has reinforced the impression that the more conservative voices in the Chinese leadership are in the ascendancy.

“The conviction and extremely harsh sentencing of Liu Xiaobo mark a further severe restriction on the scope of freedom of expression in China,” said Navi Pillay, UN high commissioner for human rights.