Ford is to close its engine plant in Bridgend next year, it confirmed today
The decision will lead to the loss of 1,700 jobs at the South Wales factory, and many more in companies supplying goods and services to the plant.
The news was being confirmed today at a meeting between company officials and union leaders.
The closure, due in September 2020, deals another huge blow to the car industry.
GMB regional organiser Jeff Beck said: "We're hugely shocked by today's announcement, it's a real hammer blow for the Welsh economy and the community in Bridgend.
"Regardless of today's announcement, GMB will continue to work with Ford, our sister unions and the Welsh Government to find a solution to the issue and to mitigate the effects of this devastating news."
Workers were being given the news at briefings inside the plant and were then expected to leave for the day.
The site opened in 1980, covers an area of 60 acres, and is one of Wales's major employers.
Ford has blamed "changing customer demand and cost" for the closure.
Ian Price, CBI Wales Director, said: “The planned closure of Ford’s Bridgend plant is a blow to the lives of all who work there and in its supply chains, as well as to the Welsh economy.
“The workers must be given every help in re-training, upskilling and finding new opportunities.
"Despite the bad news, we welcome that Ford recognises its obligations and is proposing a plan to ease the impact.
“The Welsh Government and Westminster must do all in its power to sustain manufacturing in our country, and support industries under threat from a range of challenges, from automation to a slowing global economy.”