Tesco is facing the prospect of a national strike throughout its distribution chain following a walk-out at its Livingston depot.
Drivers from the Scottish depot began a three-day strike on Thursday over terms and conditions to be introduced when they move to a new site this summer, as well as the derecognition of the T&G there.
The union fears Tesco will change conditions and derecognise it nationally and has cleared the way for a national ballot it said would involve 5,000 members.
Tesco claimed that figure would be closer to 2,000, while many drivers had already signed up to the new terms and conditions. "There is so much hot air involved in this it is ridiculous," said a Tesco spokesman. "This week T&G claims members are going to be £6,000 worse off, last week it was £3,000 and the week before it was £5,000. No one will be worse off.'
T&G spokesman Andrew Dodgshon said: "Those who have signed up to the conditions have done so under intolerable duress from Tesco and are supporting the strike. What would sort this out is if Tesco would engage in negotiations."
The T&G claimed Tesco offered Eddie Stobart drivers £500 each to breach picket lines of this weekend's strike - a claim Tesco strongly denied.