After Swedish carmaker Saab unshackled the chains that bound it to General Motors, two other subsidiaries are set to follow suit. (See: Swedish carmaker Saab looking to separate from parent GM, files for bankruptcy)

Troubled German carmaker Opel is in effect to become independent from its parent company General Motors after 80 years, under restructuring plans announced by its supervisory board. The move will also see Vauxhall, which represents General Motors in the UK, rolled into the newly restructured company and spun off from its US parent.

Hans Dechant, the head of Adam Opel GmbH said that the carmaker would "largely detach" itself from GM and reorganise as a joint-stock company to lure investors and state backing to save it from insolvency.

Following weeks of speculation about Opel's fate, GM Europe President Carl-Peter Forster told a news conference the German carmaker would be split off into a separate unit to be majority owned by its struggling US parent.

Under the plan, outside investors would take a stake of more than a quarter, bringing an end to Opel's 80 years as a wholly-owned unit of GM. Opel's UK affiliates Vauxhall would be part of the spun-off unit.

"There are still no decisions about plant closures or forced layoffs," Forster said. He added, however, that GM would be willing to sell a production site if that would help reduce overcapacity while securing jobs.

The futures of all 10 General Motors plants in Europe - including the two in the UK - are all under review. At least two plants are likely to be closed soon because of overcapacity and to cut losses.

The announcement to restructure General Motors' European operations came after protests by thousands of workers in several cities this week who called for Opel to split from GM, in an effort to save it from insolvency and protect their jobs. Opel employs 26,000 in Germany alone.

Opel said it was hoping the German state would guarantee €3.3 billion in loans necessary for the restructuring plan, making it the first carmaker in Europe to ask for government support. But the government has repeatedly struck a note of caution, calling on Opel to first come up with a workable restructuring package.

"We expect that this amount - however it is given, whether in the form of a loan or guarantee - would be paid back at the latest by 2014-2015," Foster said.

Forster said the restructuring plans would be presented to the government on Monday as well as four states in which Opel has plants. Experts warned of complications likely to arise around the issue of patents and rights. Forster said "considerable savings" of €1 billion needed to be made, and cuts in wages and voluntary redundancies were to be expected.

GM wants to present the plan, which was backed by European union boss Klaus Franz, to the German government next week. Franz has said he wants to share the burden of job cuts across Europe to save any single plant from being closed.

German Chancellor Angela Merkel, facing an election in September, wants to save as many of the roughly 25,000 German jobs at Opel as possible and the government has said it will consider offering help.

A major concern of the government is that any state aid could end up flowing back to GM, which on Thursday posted a loss of nearly $31 billion for 2008. The Detroit-based firm is itself seeking a federal bailout to stay afloat.