Every union worker at Vauxhall’s Ellesmere Port car plant has walked out in protest at planned job cuts.
John Cooper from Unite said all 1,100 employees at the site are union members and every one had gone on strike.
Vauxhall is planning a “phased reduction” of 241 jobs as part of a restructuring at its main car plant.
It said the decision was critical “to align head count and production costs for 2019 with forecasts” during a “difficult time within the industry”.
The strike follows the decision by workers at nearby shipyard Cammell Laird to walk out during industrial action over planned job losses.
Mr Cooper, the Unite convener at the Ellesmere Port plant in Cheshire, said the announcement by the company followed three previous rounds of job cuts in recent years.
“It’s like a death by 1,000 cuts,” he said.
“There’s been a growing frustration at the lack of clarity about the future. The frustration turned to anger and people took a decision. They’re walking out,” he said.
Vauxhall, which was taken over by the French company PSA Group in 2017, has announced a plan “to align headcount and production costs with the 2019 production forecasts and plans”.
In a statement, Vauxhall said: “The 2019 plan encompasses site compression, implementation of new technologies and other transformation activities which will impact on headcount requirements.
“This restructuring requires a planned phased reduction in headcount by 241 heads during 2019.”
Vauxhall employs about 3,000 people in the UK and has previously said it faces falling sales and relatively high manufacturing costs at the Ellesmere Port plant, which builds the Astra.
It now plans to consult with union representatives for at least 45 days “with a view to … reducing the numbers of redundancies and mitigating the consequences”.
Shadow Business Secretary Rebecca Long Bailey said: “This is devastating news for workers and their families in the run-up to Christmas and is especially shocking considering the carmaker’s recent return to profit.”
She claimed the government should not “allow for the decimation of such a vital industry with its highly-skilled workforce”.
Justin Madders, Labour MP for Ellesmere Port, said he would ask the PSA Group to confirm that no compulsory redundancies will take place.
The plant employs workers from across a wide region spanning north Wales to Lancashire.
“Throughout a highly uncertain and difficult time, the workers have done everything that has been asked of them and have continued to operate one of the most efficient facilities in Europe. They cannot be expected to continue to make sacrifices without any assurances on the future of the plant,” Mr Madders said.
David Hanson, Labour MP for Delyn, Flintshire, said around 350 people from Wales are employed at Vauxhall in Ellesmere Port.
He described the news as “disappointing”.
“It’s not clear what this means for the long-term future of Ellesmere Port site but I know the workforce remain committed to growing the business and continuing manufacturing,” he added.
The Department of Business, Energy and Industrial Strategy has been asked to comment.