BMW has confirmed that 850 jobs are to go at the Cowley plant in Oxford, which makes the Mini, and that weekend working has been scrapped.
All agency workers who did the weekend shift at the factory have lost their jobs, with immediate effect, prompting an angry announcement from unions.
The site is closing for a week amid falling sales in the economic downturn.
The carmaker also said it had identified 150 surplus workers at its Mini plant in Swindon.
The workers will be offered a transfer to work in Oxford, it added.
Work at the Cowley plant will not restart until 23 February. The changing shift patterns, and the resulting job losses, will come into force on 2 March.
"Mini plant Oxford will be bringing in a new shift pattern in response to continuing volatile market conditions," a BMW statement said.
"As of Monday 2 March, the plant will go from a three-shift to a two-shift pattern, operating five days per week instead of the current seven."
"The company regrets that this change will result in the release of around 850 agency workers from the business," it added.
BMW had said that all staff at the factory, including remaining agency workers, would be paid their basic wages during the closure.
However, many agency workers said they were unclear what the future held after being told the weekend shift had been axed.
Javid Najibi said he had been told to leave after four years at the plant and that he was likely to get no payout.
"It's bad News
for everybody. There's no work any more for the weekend shift. No-one knows about the future plans," he said.
Another agency worker told the BBC that he felt like a "second class" employee compared to the permanent staff.
"It's a disgrace," he said.
"I've worked here for three-and-a-half years and now I'm being sacked for no reason. I've been used."
A Mini spokesperson had confirmed at the weekend that the company was in discussions with Unite union representatives over changes to shift patterns at the plant.
"Our first priority is to communicate with the workforce," the spokesperson had said.
'Angry and upset'
However, staff were angry about the way in which they were told about their job losses.
Bernard Moss, from the union Unite said: "[The workers] obviously weren't very happy and the biggest issue was being told one hour from the end of the shift that they hadn't got a job."
Worker Silvia Fernandes said: "I've been here for four years and I've never been sick, I've never missed work and they tell me one hour before that I've been sacked. That's not on.
"That's why people are angry and so upset with BMW and the union."
The company's 4,500 staff had returned to work on 5 January after an extended four-week Christmas holiday.
In December, 300 agency staff were told there would be no more work for them at the plant after the Christmas holiday.
BMW, like most carmakers across the world, has been struggling in the face of falling sales during the economic downturn.
Overall, BMW sales fell by 4.3% in 2008, to 1.4 million vehicles, although Mini sales actually rose by 4.3% last year, to 232,425 cars.
The carmaker is the latest in a long line of car manufacturers in the UK to announce plant closures and redundancies.
For example, Honda has closed its plant in Swindon for four months between February and May. THE BBC