How open is China's global Confucius Institute programme?

In recent months a large scale school and university education programme, funded by the Chinese government, has been under attack.

Confucius Institutes, as they are known, are staffed by Chinese teachers and are now established on almost 500 overseas university campuses.

Their strong links to the Chinese state have led some western academics to accuse them of threatening freedom of thought and freedom of speech.

But little has been heard from the organisation in its own defence - until now.

John Sudworth was given a rare opportunity to interview Ms Xu Lin, a vice-minister level Chinese official in charge of China's worldwide Confucius Institute programme.