Honda plans to cut 800 jobs at its Swindon plant because of "low demand" for its vehicles across Europe.
The surprise move - which marks the first time the Japanese carmaker has made UK redundancies - comes after the company hired 500 workers last year and invested £267m in its Swindon factory.
But Honda, which has 3,500 UK employees, said the expected increase in demand had not happened, with sales of cars in Europe, including Spain, Italy and Greece, falling by a million over the past year.
The company's European vice president Ken Keir told Sky News it was a "tough day" for its workers in Swindon.
"While the UK market is stable and there's opportunity for growth, we don't see the same opportunity in mainland Europe for growth," he said.
But Mr Keir insisted the UK "still is" the cornerstone of Honda's European operation.
"Quite categorically, we have a future at Swindon and producing cars in Europe for Europe, regardless of this decision," he said.
"We've got to realign our business with the opportunity in Europe."
The company said it would hold discussions with workers in Swindon and would seek to avoid compulsory redundancies.
Last year, a third of the 150,000 cars built at the Swindon factory were sold in the UK, with the rest exported to 26 countries, mainly in Europe.
The Jazz, Civic and CR-V Honda models are built at the plant, which has an annual capacity of 250,000.
A Department for Business, Innovation and Skills spokesman said: "This will be a bitter blow to the workforce and the local area and we will be working with local partners to minimise the impact of the job losses."