Jim Farley, executive vice president and president of Ford EMEA poses next to the new Ford Vignale car at the 86th International Motor Show in Geneva, Switzerland, March 1, 2016. REUTERS/Denis Balibouse

GENEVA (Reuters) - Tariff-free trade after Brexit is vitally important to maintaining jobs at Ford's F.N British sites, its European boss told Reuters on Tuesday, amid growing concerns among unions about jobs losses at the U.S. carmaker's Welsh engine plant.

Ford, Britain’s biggest automotive engine builder, said last year it was scaling back investment at the plant in Bridgend due to lower than anticipated demand for one of its petrol engines.

Last week, unions said Ford planned to ax 1,100 jobs at the site despite the U.S. carmaker saying there were no immediate plans for cuts.

Ford has denied Britain’s decision to leave the European Union is a factor in the scaled back investment, but unions say uncertainty over the future trading relationship with the EU is harming the country’s car industry.

Ford of Europe president Jim Farley told Reuters barrier-free trade was essential to protecting the firm’s more than 14,000 British workers.

“For the future of those employees and for customers in the UK, a zero-tariff environment is really, really important,” he said during an interview at the Geneva motor show.

“We will continue to insist that a zero-tariff environment is key for the future of those employees at Ford.”

Ford’s British-built engines could face tariffs of up to 2.7 percent, while vehicle imports could be hit by tariffs of up to 10 percent if Britain were to return to World Trade Organization trading rules.