AROUND 250 workers at a chemical plant in Darwen are set to strike tomorrow after bosses announced their hours would be increased by 3.5 hours per week with no extra pay.

But bosses at Lucite International insist the move, which affects shop floor and office workers, is necessary to meet tough trading conditions within acrylic sheet manufacturing.

Under the deal shop-floor employee hours would rise from around 36 to 40 hours and for office staff from 36 to 37.5 hours.

Management is also arguing that workers contracted before 2011 earn around £31,000 per year with allowances, and occasional payments, salaries which are said to be around a quarter higher than at rival manufacturers locally.

Union leaders however say the change is “totally unacceptable” and called the proposed changes “exploitative”. A ballot saw 93.4 per cent of GMB and Unite members back a strike.

A 24-hour stoppage has been called by unions GMB and Unison from 6am tomorrow, with further stoppages on Monday, June 1 and Tuesday, June 9.

Karen Lewis, GMB’s regional organiser, said: “This is a decimation of workers’ conditions. The increase in hours is the equivalent of wiping out their entire holiday entitlement, more than 200 hours a year.

“Lucite is rooted in Darwen. They benefit from a loyal and skilled workforce many of whom have worked there for decades and the proposals are a serious erosion of hard fought terms and conditions.”

But a Lucite International spokesman at Darwen said: “Our objective in proposing the changes was to secure a commercially sustainable future for the business, the Darwen site and the town.”

“While the outcome of the ballot is regrettable, and particularly the decision of GMB members to vote in favour of a strike as well as other forms of industrial action, it is hoped that talks will continue to resolve these issues.”

An initial 30-day consultation period over the moves, said to be prompted by increased European and global competition, was later extended to 45 days.