Ford is expected to announce plans to close its engine plant in Bridgend, with 1,700 jobs under threat, Sky News understands.
The car maker has called a meeting with union leaders on Thursday, when an announcement on the future of the site in South Wales is set to be made.
As well as its 1,700-strong workforce, hundreds more people are employed in businesses that supply the plant, which has been manufacturing engines in Bridgend for 40 years.
A Unite spokesman said: “Unite will be meeting Ford first thing tomorrow morning and will comment further once the details of any announcement are known.
“Our priority is our members’ jobs, the communities and livelihoods in the supply chain that Ford Bridgend supports.”
Jeff Beck, regional organiser for the GMB union, said the closure of the plant would “mean disaster for both our members in Bridgend and the community at large”.
He added: “The ironic part is, in the week that Donald Trump is meeting the UK prime minister and talking up a special relationship and trade deal with the UK and the US, if the plant does close the new line is likely to be taken to Mexico by an American company.
“So much for the special relationship, Mr Trump.”
On the future of the plant, a Ford spokesman said: “We don’t comment on speculation.”
The expected closure is the latest blow to Britain’s car industry after Honda’s decision to shut its Swindon plant in 2021, with the lost of 3,500 jobs, and Nissan cancelling plans to manufacture its X-Trail model in the UK.
In February, Sky News revealed Ford was cutting up to 400 jobs in Bridgend in a voluntary redundancy drive – part of plans to axe many as 1,000 jobs at the plant over the next two years.
Meanwhile, the company announced last month that it was cutting 7,000 white collar jobs worldwide , with up to 550 expected in the UK.
The US-based firm employs about 13,000 people in the UK, roughly a quarter of its 54,000-strong workforce across Europe.
In April, Ford’s chairman told Sky News that it would take a “long hard look” at its UK operations in the event of a no-deal Brexit.
Steven Armstrong said Ford had already spent tens of millions of euros preparing for the UK leaving the EU without a deal, including the stockpiling of components for its factories.
“Anything that puts either tariffs or friction at the borders in place – a no-deal Brexit – would be a disaster for Ford Motor Company but also the rest of the industry,” he added.