“It would be a catastrophe,” said Håkan Danielsson, chair of the Saab chapter of the Swedish Association of Graduate Engineers, to the TT news agency.

No discussions of a possible merger are currently taking place. Rather, it is German unions who have raised the idea.

“I understand that Opel sees a benefit in adding a further brand to help secure German jobs. There aren’t any factories operating at capacity, so Opel would earn money by building Saab, but we’d simply lose out,” said Danielsson.

His assessment is shared by the head of the IF Metall union, Paul Åkerlund.

“A merger wouldn’t work,” he said.

Unions in GM-owned factories in Europe will act in concert on Thursday when they demonstrate in an effort to save their jobs.

In Trollhättan, labour leaders are planning a candlelight procession and speeches.

In Germany, the tone is more combative with talk of outright protests.

“We’re choosing slightly different approaches,” said Åkerlund.

Both Saab and Opel are suffering from heavy losses and have asked their respective governments for help to stay afloat.

Earlier, GM forced the two divisions to compete with each other.

While Opel’s factory in Rüsselsheim won the right to produce the next generation Saab 9-5, Saab’s business and restructuring plans call for all production to be moved back to Trollhättan.

Saab and Opel share a large number of common parts and have worked closely in recent years, but the two brands are already on their way to separating from one another.

The assembly of Saab wheel and brake units, which previously took place in Rüsselsheim, is in the process of being moved to Trollhättan, according to TT