Tony Trench, T&G section of Unite regional industrial organiser, said in spite of the 'Fort Wapping' style security clampdown it was clear all was not well.

"We have been told by very good sources that only twenty five per cent of normal loads are going out and there has been a seventy per cent reduction in order picking," he said from the picket line. Public support for the drivers was also very encouraging, he added.

The union also said the prospect of a national ballot was now very real. Ron Webb, T&G section of Unite national secretary for transport, who was on the picket line at Livingston yesterday and led a rousing rally of the drivers, today warned that "as things stand we'll be starting a national ballot of our members across the other distribution sites."

"Tesco are being hit by the Livingston strike and in denial about what it is all about," Mr. Webb continued. "We will start the national ballot unless the company commits to meaningful talks with us."

The drivers walked out at midnight yesterday and will stay out until midnight on Saturday 26th May. The dispute, involving nearly one hundred and fifty drivers, is over changes to their contracts, which will mean losses to the drivers of between £3,000 and £6,000, and the derecognition of the union as the depot is moved just 500 yards down the road.

Drivers voted by 126 to 6 to strike in a ballot where over nine out of ten took part. T&G section of Unite leaders have also said the dispute could escalate into a national campaign including the ballot.