Nestle has announced plans to cut 645 jobs at its largest UK factory.
The Swiss-owned confectionary firm said that it hoped to achieve at least half of the job cuts at its factory in York through voluntary redundancy or early retirement.
Redundancies at the plant in the northern English city will take place next year and in 2008.
Under future plans for the York plant, Nestle plans to sell off Victorian parts of the site, while making a £20 million investment in more modern facilities at the factory, which will continue to employ more than 1,800.
The restructuring process will also see the production of key Nestle brands moved out of the UK , with chocolate treat Smarties to be manufactured in Germany , while the company's Black Magic range is now set to be made in the Czech Republic and Dairy Milk production moved to Spain.
Nestle, which acquired rival chocolate-maker Rowntree in 1988, said that the changes were necessary in an increasingly competitive market.
Nestle UK chief executive Alastair Syke said: "The UK confectionery market is very competitive.
"Our Nestle Rowntree business has market-leading brands and strong potential, and this restructure and investment programme will ensure that it is competitive and fit for the future."
Unions have described the planned job cuts as "devastating" for both the people of York and workers employed at the factory and have vowed to fight the redundancies.
John Kirk, organiser for the GMB union in York said: "This announcement will be devastating to the people of York and to the long serving GMB members who work in the factory.
"Nestle's reasons for exporting so many jobs - namely that the plant and buildings are old and out of date - are self serving," he added.
"Nestle took the profits from the brands year in and year out and Nestle themselves failed to invest adequately in the plant and building in York."
News of the planned job losses will not be welcome in York, where Terry's and British Sugar have also announced redundancies in the past year.
Meanwhile, insurer Aviva, owner of Norwich Union, announced plans to cut a further 450 jobs in the city only last week.