More than 3,500 workers and shoppers have signed a GMB union petition urging the Competition and Markets Authority to block the merger between Sainsbury’s and Asda.
In February,a report by the watchdogoffered two options – completely blocking the merger or potentially ‘divesting’ the combined business of hundreds of stores and depots.
GMB, the trade union that represents Asda workers, formally responded to the CMA’s provisional remedies for the merger on 7 March.
GMB national officer Gary Carter said: “Today we’ve written to the CMA to let them know that that we – and thousands of other people – don’t think this merger can now go ahead.
“GMB was not opposed to the merger – but based on the CMA’s own evidence, we now have to take a position.
“It will be incredibly damaging, and the only rational response is to stop it from going ahead.
"What Asda workers need is certainty and job security. The price shoppers and workers face paying for this merger is simply too high.”