Britain's biggest carmaker Jaguar Land Rover said a so-called "hard Brexit" would cost it 1.2 billion pounds ($1.59 billion) a year, curtailing its future operations in the United Kingdom.

"We urgently need greater certainty to continue to invest heavily in the U.K. and safeguard our suppliers, customers and 40,000 British-based employees," JLR's Chief Executive Ralf Speth said in a statement on Wednesday.

JLR joins a growing list of companies which have raised concerns about potential disruption to business if Britain crashes out of the bloc next March without a trading agreement with the European Union, a so-called hard Brexit.

"The recent statement from JLR only reaffirms this position that a Brexit which increases bureaucracy, reduces productivity and competitiveness of the U.K. Industry is in no-one's interest," JLR's Indian parent firm Tata Motors Ltd said in a statement on Thursday.

Shares in Tata plunged to their lowest in more than five years on Thursday, as investors turned jittery on the company, whose biggest business is JLR, which contributed nearly 77 percent of its total revenue in the year ended March 31, 2018.

"Prima facie, 1.2 billion pounds looks on the higher side and hence the reaction to the stock today," said Basudeb Banerjee, an analyst with Ambit Capital.

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