Trade and Industry Secretary Alan Johnson has revealed a "healthy scepticism" about the return of car production at MG Rover's historic Longbridge home.

Ex-Rover workers should not hold their hopes out for a return to work there despite the £50 million acquisition of the company and its assets by Chinese firm Nanjing Automotive, he said during a visit yesterday.

Meanwhile, it emerged that Nanjing only plans to take around 40 acres of the giant 330 acre sites, fuelling fears a research and development facility may only be established there.

Mr Johnson visited the Longbridge area yesterday to see the wives of ex-Rover workers and see how many had found jobs and training opportunities.

He said he had no doubts Nanjing could finance the deal, but thought this may not necessarily involve Longbridge.

He said: "I hope car production comes back to Longbridge. People need hope, but they do not need false hopes.

"They have been led up so many garden paths in the past. Quite frankly, I have a healthy scepticism about car production being returned to Longbridge."

Mr Johnson said it would be wrong for workers to wait for jobs at MG Rover, despite claims by Nanjing that up to 2,000 posts could be created.

He said: "There has been a lot of progress in the 13 weeks since MG Rover collapsed.

"Lots of people have found new jobs, training or are waiting to go on new training courses.

"But we should not pretend that everything is coming up roses, it is still very difficult for lots of families, with increases in debt and lots of people still on job seekers allowance."

From the 6,000 who were made redundant when Longbridge closed in April, 1,750 had so far found work, with 1,600 starting courses and 1,400 booked onto retraining courses.

Mr Johnson said: "Lots of people want to become driving instructors, but there are not enough people to train them at the moment.

"People should not rely on getting a job back at Longbridge, quite the opposite.

"There is a healthy scepticism about how many how many jobs are going to be created.

"Maybe it will result in a research and development facility and some manufacturing at Longbridge, but don't bank on it.

"If it does happen it is not going to be a for a long time, much needs to be resolved and a year away is the best estimate."

Mr Johnson advised exworkers to stick to their plans and prepare for the worst case scenario with no new jobs being created.

But he added that support would come from the DTI to help Nanjing's plans.

DTI officials had been in discussions with the Chinese carmaker, although he had remained out of the talks.

He said: "Nanjing has not asked for any money. You have to be very wary of companies who want the taxpayer to put in money who have not got a business plan to raise the money on the markets."

A spokesman for Nanjing said it was "very likely" Longbridge would be the place for the UK design and engineering and manufacturing facility.