GENEVA, March 7 (Reuters) - Britain's biggest carmakers such as Jaguar Land Rover cautioned Prime Minister Theresa May that car plants would become more expensive and more complicated to run after Brexit unless she can ensure unfettered trade with the European Union.
Ahead of Britain's exit, the world's biggest car companies are grappling with how they will import millions of components from around the world and then export cars made at British factories to European clients after a Brexit transition ends.
Carmakers are already drawing up plans to handle multiple scenarios including tariffs and delays at ports which would hit a global business model reliant on the swift movement of components, engines and finished models across borders.
"It costs us two-digit million number of pounds which is absolutely wasted if the one or the other condition is going to happen but at the end of the day we cannot risk the company," Jaguar Land Rover (JLR) Chief Executive Ralf Speth told Reuters at the Geneva Motor Show.
"We are talking about minutes at the borders and if we are out of the minutes, we have huge disadvantages in terms of inventory, logistics and therefore we have to do all this kind of contingency planning now," said Speth, who heads up Britain's biggest car company.
He also warned that any divergence in vehicle standards between Britain and the European Union, which are currently the same, would be a "fallback to the Middle Ages."
Whilst London and Brussels hope to agree a transition deal at an EU summit this month which will maintain the status quo until the end of 2020, companies are already trying to plan for an uncertain long-term future in Britain.
At stake is the success of one of Britain's few manufacturing success stories since the 1980s: the car industry employing over 800,000 people and generating turnover of 77.5 billion pounds ($110 billion).
BMW and other companies will meet May and her finance minister, Philip Hammond, on Thursday to discuss Brexit, a spokesman at the German carmaker said.
Honda and Peugeot are also among those looking into building extra warehousing to hold larger stocks of components to protect their "just-in-time" production models from any customs checks which could introduce delays after Brexit.
BMW's Mini said the complications of preparing for a loss of unfettered trade were huge.
"We don't know if each truck gets held up. We can build up bigger stocks so that we are more flexible in production. It is a nightmare right now," said board member Peter Schwarzenbauer.
Honda's European Government affairs manager, who told parliamentarians last year the Japanese carmaker would need to trigger its contingency plans this month, told Reuters the firm was awaiting further detail.
"We are monitoring the situation as the negotiations unfold and look forward to receiving additional clarity at the March council," said Patrick Keating. (Additional reporting by Edward Taylor, editing by Guy Faulconbridge)