A self-appointed internet ‘rumour buster’ has triggered a public debate over the way China distributes and controls information, in the latest episode of the ruling Communist party’s complex engagement with the country’s wildly popular microblogs.

Dou Hanzhang, a former journalist at the official news agency Xinhua, has been bombarded with criticism over the past week over his attempts to “unmask” news spread by microblogs as false via a “Rumour-busting League” set up earlier this year.

The league claims to have exposed more than 100 rumours on its microblog since it was founded in May. But it gained prominence only after it denounced as a rumour the news that the government was burying evidence at the site of a rail crash which killed at least 40 people last month.