Scheduled for next Wednesday (13 February), the 24-hour walk-out is the final day of action in a monthly series of strike days which have taken place since November last year.

Further strike action has been proposed by Unite in the run-up to the Easter holidays if management does not enter into talks over pay. Staff at the Beccles plant have seen two pay rises in the last 14 years, with the most recent being a 1% bump in 2017.

Voting on strike action was tabled after CPI management proposed a two-year pay freeze last April and the motion passed with a 71% majority.

According to Unite, CPI management has “adamantly refused” to offer an alternative proposal in the time since the previous strike day in January.

There are 75 Unite members working for the CPI Group subsidiary out of a workforce of 110 staff. It is not clear whether the base will be able to sustain its full operations on the remaining 35 staff during the strike.

An overtime ban is in place and it is unclear whether Unite will need to renew its mandate for strike action with a new vote to extend the monthly walk-outs beyond February.

In a statement, Unite regional officer Mark Walker said: “The management at CPI William Clowes needs to recognise the continual hard work that our loyal members put in year in, year out.

“The management claim that they want to resolve this dispute, but have shown extreme reluctance in putting a firm pay proposal on the table.

“The members have shown a great deal of resilience and solidarity during this dispute, buoyed up by the support from the local community.”

CPI had not responded to request for comment at the time of writing.