US-China trade breakdown rattles markets

Stock markets around the world have fallen sharply amid fears of a further deterioration in US-China trade relations. Tensions in Germany's coalition government over migration policy added to investors' uncertainty. Among markets to tumble about 1 percent were those in Germany, France, Spain, Japan and South Korea. On Wall Street, the Dow Jones and the S&P500 are also down. Guyon Espiner talks to John Authers, a senior markets commentator for the Financial Times.