China Tate artist Weiwei speaks about house arrest

The Chinese artist behind the sunflower seeds exhibition in the Tate Modern says he is under house arrest in Beijing.

Ai Weiwei says it is to stop him attending a party at his art studio in Shanghai, which is about to be demolished.

He says he expects to be released from house arrest on Sunday. He told the BBC's Martin Patience what makes him think the government doesn't want him in Shanghai.