Pickets at Sierra Windows in Paignton, Devon, had angry words for their union official on Tuesday.
They were starting what should have been their first three-day strike after a series of two-day strikes.
But Unite union regional coordinating officer Terry Keefe told them an “administrative error” meant that they had to work on Wednesday but strike on Friday.
Next week’s strike is to be on Wednesday, Thursday and Friday, instead of starting on Tuesday, generally the busiest day. Very few workers are in on Fridays.
Workers have signed a letter to Unite regional secretary Peter Hughes asking how the error happened and how it will be rectified.
Keefe said workers may not get a 12-week extension on their strike ballot when it runs out next month.
He suggested bosses might shut the place down if it doesn’t make enough profit. One worker replied, “If they shut down we’ll look for other jobs—but we have to make a stand.”
Workers are fighting a below-inflation pay deal and new 12-hour shift patterns.
Unite members at DB Glass, the other unionised site of the Specialist Building Products group, were also on strike.