Nanjing, the Chinese company which bought the collapsed MG Rover last year, has more than halved the number of cars it had pledged to make at Longbridge.

The state-owned company now plans to build only around 4,000 MG TF sports cars each year at the Midlands site, a spokeswoman said. Production could be increased if demand for the sports car was high, or cut back even further if sales failed to take off, she said.

The company planned to employ 400 people at the site, but only "when we reach a certain level of production". She could not say what level of production would be needed for all those workers to be employed. Before MG Rover went into administration last April, 6,000 people worked at Longbridge.

Nanjing signed a 33-year extension to the lease on the Longbridge site with the owner, St Modwen, in February. But it inserted an option allowing it to cancel this extension in July. The company will not exercise this option next month, the spokeswoman said.

Nanjing's commercial director, Wang Yaoping, said in April it planned to build between 10,000 and 12,000 cars a year at Longbridge, down from the 100,000 it had originally predicted when it took over the site.

The figure of 10,000 to 12,000 was contingent on receiving at least £10 million in British government grants. Now Nanjing has decided not to apply for Government help, resulting in the scaling back of its business plan.