According to the union, the plant's management have failed to negotiate changes with to terms and conditions with the union, leading to a 12-week strike plan, which began at midnight.

However, API Foils Europe managing director Will Oldham, who joined the company in January, told PrintWeek that he was disappointed with the union's action.

He said: "This damaging strike action by Unite is very difficult to understand. There is no clear reason for the strike and a reluctance on the part of the union to detail their various concerns. Most worrying is the refusal of Unite to sit down and discuss these concerns face-to-face despite numerous requests from the company to meet.

"We have no intention to impose changes to existing terms and conditions or to change the existing collective bargaining agreement, merely to have constructive discussions with the workforce and their appointed representatives."

Oldham added that the company was taking a number of measures to minimise the effect of the dispute on customers.