Thousands of jobs could be at risk in Coventry and Warwickshire because of the sale of Rover by BMW.
But 2,400 jobs at Gaydon are safe as they will be transferred to Ford as part of the £2 billion sale of the Land Rover division.
Hundreds of firms in the area are waiting to find out if their contracts to supply the Longbridge plant will survive the sale of the firm to Alchemy.
Business leaders say around 400 firms in Coventry and Warwickshire face an uncertain future while the exact implications of last week’s sale become clear.
Alchemy plans to run the Rover operation down at Longbridge, with only a fraction of its 8,000 workforce expected to stay on.
Eventual plans are to switch production to a high-quality sports car under the MG badge.
Shifts were being cut back at the factory today, with workers being told they could lose up to £80 of their monthly pay.
Rover’s headquarters at the Warwick Technology Park will be switched to Alchemy as part of the main deal.
Isabella Moore, president of the Coventry and Warwickshire Chamber said: “Concerns remain about the impact on jobs down the supply chain throughout our region. We appreciate it is early days yet, but we also have concerns on the impact of lower volumes of supplies. There are probably 400 suppliers in Coventry and Warwickshire who are in some way or other dependant on Rover business.
“We are concerned that some thousands of jobs will be lost in the area in the automotive supply chain.”
Nick Madeley, area director of The Chamber, said the deal with Alchemy seemed “to be the best available right now, although very risky.”
He added: “The MG brand may have a more secure future as a low volume niche player than Rover cars would have had. The Chamber always had some doubts about the viability of the BMW plan – and sadly we have been proven correct.”
Help and support is being offered to any firms in the area that have been affected by the move. Contact The Chamber’s information department on 01203 654321.