AEROSPACE

Worst case Although WTO rules mean there are no export tariffs, non-tariff barriers such as customs rules persuade manufacturers to relocate production to Europe, decimating UK aerospace, which employs 95,000 people and turns over £31 billion a year.

Best case A fall in sterling outweighs border trade friction and Britain’s aerospace manufacturers and component makers — BAE Systems, Rolls-Royce, GKN and others — continue to thrive.

Unknown factor Expertise, research and production is so entrenched in Britain that it is almost unthinkable that big global manufacturers would stop working with UK suppliers but no-deal could accelerate the move of the supply chain to China and southeast Asia.

AIRPORTS

Worst case The average of 25 seconds it takes for a British passport to be