UK government business secretary [minister] Peter Mandelson has said he does not believe Magna International’s plan for Opel is “commercially the most viable”.

In a letter to European competition commissioner Neelie Kroes, Mandelson said Magna’s plan was more expensive than that of rival bidder RJH International, the BBC reported.

Unions fear that 1,100 jobs at the two Vauxhall plants in Britain could be lost under the plan.

A Department for Business, Innovation and Skills spokesman said Kroes had spoken to Mandelson since receiving the letter in which he urged the European Commission “to ensure a commercially-based outcome rather than one determined by political intervention and subsidies”.

Magna’s request for EUR4.5bn (GBP4.5bn; US$6.5bn) in German government aid is EUR 1.3bn more than a bid from investment group RHJ International would have cost taxpayers, Mandelson claimed.

“We do not believe that Magna’s offer is the best available plan,” Mandelson said.

Concerns are growing at GM factories across Europe after it became public that 10,500-11,000 of 46,000 jobs would go under Magna restructuring.