What caused investment in the UK's automotive industry to fall after several years of strong growth?

Investment in the UK's automotive industry fell in 2016 after several years of strong growth, according to the head of the industry's trade body. Some investment decisions are also on hold until there is clarity about the UK's post-Brexit trading arrangements. Mike Hawes, chief executive of the Society of Motor Manufacturers and Traders, says that investment appears to be falling back. James Brydges has been speaking to David Bailey, Professor of Industry at Aston Business school, and first asked what percentage of cars built in the UK would be exported.