The distribution network at the supermarket giant Asda is facing severe disruption after union leaders called a strike ballot among thousands of workers.
Talks aimed at settling a dispute at the company's Dartford depot broke down yesterday and the GMB general union is to hold a vote on industrial action at the group's 19 depots, which supply the whole network.
Management at the warehouse in Kent are threatening to tear up a union bargaining agreement next Wednesday if the GMB fail to sign up to a "modern" negotiating arrangement.
The GMB officers dealing with Asda are to seek official approval for the ballot from the union's national executive on Monday, but unless the company withdraws its ultimatum, the vote is certain to go ahead.
Earlier this month Asda was forced to pay £850,000 to staff at its depot in Washington, Tyne and Wear, for unlawfully offering them a financial inducement to give up their union rights. Jude Brimble, GMB national officer responsible for Asda employees, said management had been guilty of a "litany" of initiatives which had upset members.
"They've now gone too far by issuing the unilateral threat to end the agreement at Dartford," she said.
A spokeswoman for Asda said management had been in discussions with the GMB since last April about a new collective bargaining agreement and were confident agreement would be reached before the deadline.
She said the existing agreement needed updating because it included elements that were unlawful under new legislation. She said there had been a "constructive" meeting yesterday.