The production line is a whirring mass of rollers, wheels and pipes, monitored by men at computer panels. Forklifts zip about a storeroom carrying vast rolls of paperboard. This is the factory of Orient Paper, a US-listed company that Muddy Waters, the short seller, attacked two years ago as a virtually worthless fraud.

Orient Paper was the first of the eight companies targeted so far by Carson Block, whose Muddy Waters outfit shot to prominence in 2011 when its claims of fraud felled Sino-Forest, a Toronto-listed Chinese forestry company that once had a $4bn market value. Since then, Mr Block’s reputation has become so established that his views are headline news and often send targets’ share prices plunging.

“There are no companies on which we have written where we have made mistakes,” Mr Block told the Financial Times. “We really dig into these companies.”