Union officials have been told Cadbury is to go ahead with the closure of its chocolate factory at Keynsham near Bristol with the loss of 500 jobs.
The factory will finally close in 2010 with production moving to Poland
The news follows more than four hours of talks between unions and management at a hotel in Warwick on Monday.
Unite union spokesman Steve Preddy said it was bitterly disappointed at the news and would continue to fight the decision for its members.
On Monday Cadbury confirmed its decision to go ahead with the closure.
In a statement the company said: "Cadbury can confirm that it has considered the union's alternative proposal for Somerdale (Keynsham) but has told them that, unfortunately, it would not sufficiently reduce costs to a level at which we were able to compete effectively with other UK confectionery manufacturers.
"Cadbury is therefore informing employees at its Somerdale factory in Keynsham it will proceed with the phased closure of the site as part of the restructuring of its UK manufacturing base."
Steve Preddy added: "The union put forward a business plan to help save the factory but the management said it was unable to accept this and moves to wind-down the Keynsham factory by 2010 would go ahead.
"Our members our angry and disappointed by the news. Moving the production line to Poland holds enormous risks."
Last October Cadbury bosses announced the Keynsham plant was to close in 2010. Workers have staged a series of marches in protest at the decision.
Monday's meeting marked the end of a 90-day consultation period between management and unions over the plan.