Britain's exit from the EU is causing a lot of nervousness among the country's business leaders. Prime Minister Theresa May is seeking to provide more clarity on that front as she attends an EU Summit next week to outline in more detail what Britain wants from the Brexit talks. As our Richard Bestic reports, the air of uncertainty is especially worrying for the British car industry.

Global demand for cars made in Britain is running at record levels, according to the Society for Motor Manufacturers. Eighty per cent of cars made are for export – 56 per cent for the European Union.

But if the UK falls out of the EU's Customs Union, all that could change dramatically. It's at Britain's Ports where the biggest hold-ups could occur for the motor industry's complex supply lines. The average UK-built car has about 6,000 parts and the majority comes from the European Union,

With some parts crossing borders between Britain and the EU several times. Many factories hold just a few hours of supplies meaning even a short uphold could result in factories shutting down. A report by a Parliamentary committee concluded retaining good access to the EU single market would be more important to jobs and investment than the freedom to strike up new trade deals, one of the implied merits of Brexit. However, UK Prime Minister Theresa May has already ruled out remaining inside the EU Customs Union.

The UK government has also been warned British cars won't qualify for a free trade deal after Brexit because most of the parts in a British car aren't sourced in Britain.

All that poses a threat to thousands of jobs in Britain and billions of dollars in exports, according to motor manufacturers in Britain. Britain's biggest car manufacturer, Jaguar Land Rover has already announced production of its Land Rover Discovery model will be transferred to a plant in Slovakia.

RICHARD BESTIC LONDON "It's difficult to overstate the importance of the auto industry to the UK economy can't be understated. But since the Brexit referendum two years ago, investment in cars and parts has dropped by more than half, a measure according to some of a prevailing Brexit uncertainty. RB CGTN London."