A joint venture between UK carmaker MG Rover and China's Shanghai Automotive Industry Corp (SAIC) would result in job losses in Britain although it was still unclear how many, a union said yesterday.

The Transport & General Workers Union (TGWU), which represents more than 6,000 workers at MG Rover's Longbridge plant in central England, said most mergers led to job losses and a tie-up with SAIC would be no exception.

"What is important right now is to make sure we secure the much-needed investment for Longbridge to save and preserve jobs in MG Rover and in the component suppliers," said Tony Woodley, Transport and General Workers Union General Secretary.

Mr Woodley said he could not confirm a newspaper report that up to 2,000 factory workers at the plant would lose their jobs if the tie-up was successful. Production of the British carmaker's Rover 25 model and some engine manufacturing would switch to China from central England, the Financial Times said, citing sources close to negotiations.

Unions have accepted that the country's last British-owned volume carmaker would probably go bust without the China deal.

An MG Rover spokesman declined to comment on possible job cuts but said progress was being made.

About £1 billion is expected to be injected into the joint venture which aims to rejuvenate Rover's model range and give SAIC a foothold in Europe.

A deal is expected to be finalised in the spring.