A UK car plant that directly and indirectly employs more than 6,000 people may be forced to close within days, a trade union leader has warned.
Unite joint leader Tony Woodley refused to name the facility in question, but said it needed urgent state aid to stay open.
Business secretary Lord Mandelson declined to comment, but urged people to "stop feeding the rumours".
The comments came after data showed UK car production slumped in January.
"We've got a car plant that, within just a couple of days, would have run out of cash and needs serious financial help to stop over 6,000 people losing their jobs," said Mr Woodley.
He said the government had to act to prevent "a catastrophe".
Lord Mandelson said: "Rumours can very easily turn into a shockwave that destabilises a company or an industry and brings about the very outcome that we are seeking to avoid."
He added that the government would help if it could.
New car production in the UK fell dramatically in January from a year earlier, according to the Society of Motor Manufacturers and Traders (SMMT).
Aston Martin: Extended Christmas shutdown and 600 redundancies. Three-day week
Bentley: Three-day week in October and longer Christmas break. Closing Crewe plant for seven weeks from March. February announced 220 job losses and 10% pay cut.
GM (Vauxhall): Extended Christmas closure and 40-day shutdown
Honda: Four-month shutdown between February and May
Jaguar Land Rover: Series of one-day shutdowns and production cuts late 2008 plus 1,000 redundancies planned
Mini: Christmas shutdown extended by 10 days. 300 agency staff let go and one week shutdown planned for February. From March, plant will run five days per week, from seven, and a further 850 jobs to go.
Nissan: Two-week shutdown late last year and 1,200 redundancies. One shift on each line stopped until April 2009.
Toyota: One of the night shifts suspended. Four non production weeks planned
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