U.K. Business Secretary Peter Mandelson held a day of talks in Germany Thursday on the future of General Motors Corp.'s (GMGMQ) U.K. unit Vauxhall, but received no guarantees on jobs from the company's likely new owner.

Mandelson met with German Economics Minister Karl-Theodor zu Guttenberg and with Siegfried Wolf, co-chief executive of Canadian-Austrian auto parts supplier Magna International Inc. (MGA), the preferred bidder for GM's European units.

"The Business Secretary made a strong case for Vauxhall and signaled the U.K. government's willingness to commit funds" to the company, a spokeswoman for the department said.

But she said any support is contingent on the new owner coming up with a "commercially viable long-term plan" for the company and a clear commitment to Vauxhall's future.

In comments to the British Broadcasting Corp. earlier, Mandelson had said the government needed to be "realistic" about the outcome of talks with Magna.

"When you only have one player in a game like this you have to be realistic. You neither want to have terms dictated to you, because you have nowhere else to look...but you also have to accept that Magna's own interests might be revised," Mandelson said.

And while Wolf sent encouraging signals about Magna's plans for Vauxhall, he offered no fresh guarantees for the firm's roughly 5,000 workforce.

"There is a lot of potential in England and every job which is lost is one too much," he said. "I'm quite happy to find a way where, at the end of the day, it is a competitive environment where we can produce and continue with Vauxhall."

On May 30, the German government selected Magna as a partner for GM's German unit Opel and agreed to provide EUR1.5 billion in bridge financing, paving the way for a takeover by Magna and its two Russian partners.

While the U.K. initially welcomed the decision, concerns remain that the accord could lead to German jobs being saved at the expense of workers at other European GM units.

However, the German government has said in recent days that other bidders could still emerge. Meanwhile, Magna officials are carrying out due diligence at Vauxhall. Mandelson will hold further meetings with senior company officials next week.

In an interview with Germany's Handelsblatt newspaper published Thursday, Mandelson suggested he was unhappy with the choice of Magna as the preferred bidder.

He said he hoped to see a pan-European solution for the European units of GM.

"With the Canadian-Austrian parts supplier Magna we have a preferred bidder, but not a final buyer," he was quoted as saying. "In this case, more and better bidders might have been a better solution."

Meanwhile, in a speech in Berlin on Thursday, Mandelson sought to frame the European fallout from the GM troubles as a test case for effective European Union coordination in the face of the economic crisis.

Mandelson said it is natural for national governments to lead the way in responding to the economic crisis and to want to protect their workforce.

However, he said there is a "real risk that in trying to rescue parts of our banking systems and industrial base we effectively start to renationalize parts of the single market." He said that "would be a big mistake."

Separately, Mandelson called on the EU to phase out by the end of 2010 the flexibility introduced into EU state aid rules to help firms cope with the crisis.

He also reiterated the U.K.'s support of a second term for European Commission President Jose Manuel Barroso.

-By Laurence Norman, Dow Jones Newswires; 44-207-842-9270; laurence.norman@dowjones.com

(Natasha Brereton and Nicholas Winning contributed to this article.)