Last month the group said the Essex mill had become uncompetitive, and that it had entered into discussions with employees about closing the site.

GPMU East of England branch officer Geoff Usher said the decision to close had come as a shock to the union and the workforce. They said the cost of updating the equipment at the plant was too expensive, he added.

Chief executive Richard Cousins said BPB had entered into a long-term arrangement for low-cost supplies of board from its German subsidiary, Tecnokarton, a move that will reduce the companys exposure to currency movements.