A historic factory making Colman’s mustard is to close with the loss of jobs, dealing a “devastating” blow to the workforce.

Unilever said its site in Norwich will close by the end of 2019, although the company said it will protect the historic link between the city and Colman’s by retaining production of mustard powder, the mustard milling process and mint processing in a new facility in the area.

Manufacturing of other products will move to other sites in the UK, mainly Burton upon Trent, while other work will switch to Germany.

The decision will affect 113 jobs, although 40 will transfer to Burton and around 25 roles will be created in the new facility near Norwich.

Unilever said in a statement that a recent decision by Britvic to close its factory on its shared site in Norwich had “serious implications” for the company.

“We will protect the historic link between Colman’s and Norwich by retaining the production and packing of Colman’s mustard powder, the historic mustard milling process, and mint processing in a new state-of-the-art facility in the Norwich area, created through a new long-term partnership with a consortium of local farmers, backed by significant investment from Unilever. We will also continue to source our mint and mustard locally as we have for generations.

“Manufacturing of the vast majority of the other products is planned to move to other sites in the UK, predominantly Burton upon Trent, home of Marmite and Bovril, reaffirming our commitment to UK food manufacturing. The packing of dry sauces will be absorbed by existing production lines and existing employees at a Unilever factory in Germany, which already makes the dry sauce mix.

“The review concluded that the proposals announced today represent the best long-term solution for Unilever while protecting the link between Colman’s and Norwich.

“We recognise that these proposals will be difficult news for our Norwich employees, their families, and the whole community in Norwich. We are committed to supporting our employees during this difficult time. We will also offer all employees whose roles would be affected by the proposals a package of support, including redeployment opportunities at other sites, and services to help people find new employment.”

Warren Kenny, regional secretary of the GMB union, said: “This is absolutely devastating news for the workforce at Coleman’s, for the city of Norwich and for manufacturing in East Anglia.

“It is our immediate intention to speak with our members at Unilever and to seek an urgent meeting with the company and local elected representatives to fully understand what has lead Unilever to make this devastating decision, and whether there are alternatives that should, and must be considered.”

Unite national officer Rhys McCarthy said: “We are urging Unilever to look again at its business case for closure. The decision last month by Britvic to close its half of the site, which produces its Robinsons and Fruit Shoot brands, was unhelpful for the future of Colman’s Mustard in Norwich – but we still don’t believe that closure is the only option for the dedicated workforce.”