What is China's role in the Iran war?

The BBC's security correspondent Frank Gardner explains how the world's second-largest economy fits into the Gulf conflict. For one, China is the biggest customer of Iran's oil, making the US blockade of Iran's ports a major flashpoint at the moment. Watch below for his full analysis: To play this video you need to enable JavaScript in your browser.This video can not be played Frank Gardner: What is China's role in the Iran war?