LONDON (Reuters) - The United Kingdom on Tuesday announced a new post-Brexit tariff regime to replace the European Union's external tariff, maintaining a 10% tariff on cars but cutting levies on tens of billions of dollars of supply chain imports. After decades outsourcing its trade policy to the European Union, Britain is embarking on negotiating free trade agreements with countries around the world, and earlier this month launched formal negotiations with the United States. The government aims..