A video clip showing Chinese workers filling pork buns with cardboard and aired on YouTube has been branded as a hoax and its author arrested. 

The journalist, Zi Beijia, is accused of faking an investigative report, while Beijing Television has apologised for televising it.
At least seven other people have been fired or reprimanded.
The report, which shows workers stuffing buns with cardboard softened in caustic soda and mixed with pork fat and flavouring, was later aired in China Central Television and then found its way on to YouTube.
More than 6 000 people viewed the clip on the video sharing site, helping to fuel the global outcry against Chinese products.
The news comes amid reports that China's product safety agency has revoked licenses for some firms implicated in the recent spate of food and drug safety spares and banned them from exporting products.
Earlier this month, the man responsible for issuing licenses to some of these companies was executed for taking bribes.