The Essex firm, part of the Goodhead Group, has been producing 20m directories a year for BT since it took over the contract from RR Donnelley in 1997.
It has just been given three months' notice that the contract will move to Einsa Print International in Madrid, which recently lost a large contract for French directories. It is understood the decision to move the contract was based on price.
Goodhead Group managing director John Cooling said it was too early to say how many jobs at the plant, which employs 180 staff, were at risk.
"The real issue for us is the short amount of notice," he said. He added that there was "very little demand" for coldset capacity but that the company was working on various options to put more work through the plant.
"We will safeguard some [jobs] but with three months' notice, there's no way we can safeguard all of them," Cooling said.
On the plus side, Cooling pointed out that kit at the plant, which includes two Goss Universal coldset presses and a 72pp MAN Roland Lithoman, was "bought and paid for".
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