The company is to transfer production to Europe
An electronics factory on Anglesey has confirmed it is to close with the loss of 265 jobs.
Eaton Electric, which makes miniature circuit breakers, said no alternative use for the Holyhead plant was found during a 90-day consultation period.
A spokesman said a phased closure of the factory would take place between March and December this year.
Unions said the jobs were well paid for the area. The Welsh Assembly Government said it was "deeply disappointing".
The news was confirmed to workers at a meeting at the factory on Wednesday morning.
Birmingham-based Eaton Electric announced in October it planned to move the Holyhead plant's work to Europe where production costs are 35% lower.
Company spokesman David Sturge said no alternative uses for the factory or its workforce had been indentified in the consultation period with employees, employee representatives and local government bodies
An assembly government spokesman said today's decision was "deeply disappointing" and a "serious blow" to the workforce.
"The Welsh Assembly Government has done everything it can to work with the company to explore the possibility of continuing the existing operation in Holyhead but it has proved commercially impossible to devise a sustainable future for the plant," said the spokesman.
"We are continuing to talk to the company in order to help them retain some part of the operation on site although we still have a lot of work to do before the company can come to a decision."
Mr Sturge said: "The potential closure was initially announced last October following on-going efforts to increase efficiency and continue to optimize global competitiveness.
"No alternatives were identified during the 90 day consultation period.
He added that the firm was continuing to talk to the Welsh Assembly Government about the possibility of retaining a small aftermarket operation in Holyhead, although no further details were available.
"Officials and will continue to work closely with support agencies for retraining and career transition, " said Mr Sturge.
"Eaton is acutely aware of the impact this announcement will have on our employees and their families and regrets that these actions are necessary.
"We will ensure that those affected are treated with care and respect during this difficult time," he added.
The assembly government said its first priority was to help workers find suitable alternative jobs or retrain.
An on-site support centre is being opened to help employees find work.
Glyn Haynes, plant convenor for the Unite union, said the jobs in Holyhead are relatively well-paid for the area and that an enhanced redundancy package for staff has been negotiated.
"But at the end of the day, it's no substitute for your job, is it?" he said.
He said that there are hopes of retaining a small "after-market operation" which means keeping staff on to make spare parts for products still widely used but no longer produced as one of the company's main products.
Mr Haynes said that might amount to about 30 jobs.
He added that he hoped the assembly government would be able to attract another electronics company to the site.