More than 400 workers at Molson Coors brewery in Burton-on-Trent will be balloted for strike action in a row over pay and shift patterns.
Unite the Union claim 450 staff will be sacked after June 14, and then reinstated on lower pay and inferior terms & conditions.
It says some staff could lose up to £9,000 a year in the shake-up. Unite said that it had given the management seven days notice of the ballot which runs from 30 April to 28 May.
The brewery produces Carling, Grolsch, Coors Lite and Cobra lagers, as well as beers including Worthington, White Shield and Stones.
More top news
13 people have been jailed over a Nottinghamshire gang which used secret compartments in cars to smuggle drugs and money across the UK.
Footballing legend Sir Bobby Charlton will be in Dudley on Saturday to unveil a blue plaque commemorating his best friend Duncan Edwards.
The father of two says it will help him get back his independence and plans to return to work in the next few months.