Utopia had been allowed to flourish since it was founded in 2003 and soon became the platform for China’s resurgent hard left. It opposes privatisation of the economy and other Western-style reform, and has at times been critical of China’s leadership, while promoting the achievements of former leader Mao Zedong.

The website has also been at the forefront in defending the movement’s figurehead, Bo Xilai, who is at the centre of the nation’s worst political crisis in two decades.

Mr Bo had won significant support within the upper echelons of the Communist Party for his campaign to spread ‘‘red’’ nostalgia throughout China, including via the singing of Communist songs. But Mr Bo was removed as Chongqing party chief after an embarrassing betrayal that saw his former right-hand man, Wang Lijun, visit the US consulate in Chengdu in February, reportedly linking him with the death of a British national Neil Heywood.

The daily ‘‘red concerts’’ Mr Bo ordered in Chongqing have been removed from television programming. The billionaire boss of conglomerate Dalian Shide, Xu Ming, has been detained due to his close links with Mr Bo.

The Utopia website had also been taken offline in the days following Mr Bo’s sacking. Other left-wing websites Mao’s Flag and China’s Election and Governance have also been shut down.