Meanwhile management at Corning Optical have confirmed they are closing their entire operation on Deeside with the loss of over 400 jobs.

Both companies are major employers in north and south Wales and the moves are seen as a significant blow to the economy.

GE's operation in Nantgarw is a cornerstone of the aviation industry and is one of the few plants worldwide where airline engines are overhauled.

Even before the 11 September US terrorist attacks business at the site was suffering and 250 jobs losses were announced in June.

Now, with confidence in the airline industry at rock bottom, GE looks set to cut even deeper.

Shutdown

According to sources in the plant, the workforce have been told of another 350 redundancies, however the company have yet to confirm these details.

Caerphilly AM Ron Davies said the GE announcement was a "bitter blow".

Meanwhile, the American-owned Corning Optical, which announced the loss of 125 jobs last month, has revealed that the plant will now close entirely.

The factory, which makes optical cables, is one of Wales's most signifigant players in the high-tech industry and is the biggest such plant in Europe.

Ron Davies: Call for government support

Now the slump in the telecommunications industry - coupled with the aftermath of the terrorist attacks - has led to its closure and the loss of a total of over 430 jobs.

Management at the firm have said the shutdown of the factory is under discussion but operations will be wound down immediately and will cease by the end of the year.

European communications director John O'Hare said the Dow Corning decision was a direct impact from a reduced order book.

A reversal of the decision seems highly unlikely at this stage.

Most of the staff at the site are believed to have been sent home on Thursday and told to contact the company on Monday.

Ron Davies has called on the UK government to look at providing support for aviation businesses in south Wales.

"This situation is having a major impact in south Wales. Given the cooperation the workforce has shown in slimming down, it is a bitter blow. Nantgarw is a world-class facility.

"I think the industry in south Wales deserves consideration from the government."