Tony Blair has promised to look into the closure of Tesco's Dundee depot after an MP raised concerns about 400-plus job losses during Prime Minister's Questions.
A Tesco spokesman said: "The issue was raised with the PM on the premise of asking Tesco to offer a fair deal to our staff. We have always had every intention of doing that."
Meanwhile, Asda is facing the threat of national strike action after the GMB declared a ballot would take place next month across all of its 21 depots in a row over national bargaining on pay, bonuses, working conditions and facilities.
The GMB is also fighting new rotas at stores that will involve staff working three Saturdays out of four per month.
In a demonstration scheduled for today, union members were set to be out with placards, stating 'Asda Sally practice what you preach'. It is a reference to Asda's retail MD for the north, Sally Hopson, who was a panel member on the government's Women and Work Commission.