Fighting tigers: China's power struggle

In China - the disappearance of the country's former spy chief - is seen as evidence of a major power struggle.

Zhou Yongkang vanished late last year - suspected of corruption.

He was once one of the most powerful men in China but his name has not been mentioned officially in over 160 days.

An estimated £8.5 billion of his family assets have been seized and many of his allies have been arrested.

Now China waits to see if President Xi Jinping can keep such a powerful enemy out of sight.

The BBC's China editor Carrie Gracie reports on the mystery of the missing security chief.