Chocolate firm Terry's has revealed it plans to close its site in York with the loss of more than 300 jobs.
York has been synonymous with chocolate making for 200 years
Parent company Kraft Foods is to switch production to central and western Europe in the second half of 2005.
Plant director John Pollock said: "It's a very difficult time. The relationship between the company and the city of York stretches back many, many years."
A City of York Council spokesman said: "This is obviously terrible news for the UK chocolate industry and York."
The York plant produces confectionery products for the domestic and international market including Terry's Chocolate Orange, Terry's All Gold and Twilight.
Future production is expected to be transferred to Kraft's existing facilities in Sweden, Belgium, Poland and Slovakia.
City of York Council chief executive David Atkinson said: "Terry's association with York goes back over two centuries and its name is synonymous with chocolate making in the city."
Terry's of York
1767 - confectioners Bayldon and Berry founded
1823 - Terry's name first appears when Joseph Terry becomes a partner
1886 - Joseph Terry Jnr builds chocolate factory in Clementhorpe, York
1923 - Frank and Noel Terry join the business and launch the Chocolate Orange
1939 - During the Second World War the factory makes aeroplane propellers
1975 -Terry's of York acquired by United Biscuits.
1993 - Kraft General Foods buys Terry's Group from United Biscuits and amalgamates it with Jacobs Suchard to create Terry's Suchard
2004 - Kraft announces closure of Terry's site
The company's links with its home city were reflected in the Terry's of York name stamped on all products until four years ago.
In 2000, its link with the city began to be phased out and since 2002 its products have been sold under the simplified name Terry's.
Mr Atkinson said the city council city had prepared a support package for the staff who face redundancy.
Details of the package had yet to emerge, he said, but there would be "continuing dialogue between the council and senior management at the company".
The company said the closure "reflected a recent decline in export volumes that, together with the size and configuration of the site, has resulted in a cost structure that is unsustainable for current production levels".
Mr Pollock said: "We simply have no choice but to continue improving our cost structure if we are to be able to invest in growing our brands.
"The York employees have made terrific efforts over many years to improve efficiencies, but given a combination of factors it has not been possible to preserve the plant.
"Our clear priority now is to discuss the situation with the unions and each and every employee over the coming days and weeks."