Britain, the world's fifth largest economy, is due to leave the European Union, the globe's biggest trading bloc, in 66 days but the government's negotiated deal was rejected by lawmakers, leaving open a number of possibilities such a disorderly Brexit.

The car industry, which employs over 850,000 people in the country, has warned that any tariffs and customs checks would hit firms such as Bentley's parent company Volkswagen as it both exports from Britain and imports vehicles and components.

Bentley, which posted a 137 million-euro loss in the first nine months of last year, is undergoing a turnaround under a new boss and is on course to return to the black, Chief Executive Adrian Hallmark said, but that plan could be undone by the form Brexit takes.

"It's Brexit that's the killer," he told Reuters.

"If we ended up with a hard Brexit... that would hit us this year because we do have a potential to get beyond break-even to do the turnaround."

"It would put at fundamental risk our chance of becoming profitable."

Like fellow carmakers, the high-end brand is taking a number of steps, including building up stocks of imported parts from two days to 10 days and building a higher proportion of cars for some non-European markets in the next few months.

"We will build more cars for China or the U.S. than we would normally do in the six-month period," said Hallmark.

Hallmark said he believed the company was prepared and did not plan to temporarily halt output after Britain leaves the bloc on March 29, as planned by fellow automakers Mini and Honda.

"Carry more stock, and it's a few million (pounds) per year...If we had to stop production, then that would be a similar value per day," he said.

Hallmark said there are three possible outcomes on Brexit: a deal by March 29 which has a "fairly low" probability, no deal with "a degree of unrest and chaos" or an extension to Britain's EU membership.

(Reporting by Costas Pitas; editing by Guy Faulconbridge)

By Costas Pitas