Asda has threatened to scrap the bargaining agreement of a workers union over a row to introduce a “modern agreement” at its distribution centre in Dartford, Kent.

Reports claim that in a letter to the GMB union, Marie Gill, Asda’s head of industrial relations for the distribution network said: “Unless we can make substantial progress within the next four weeks in negotiations concerning the new arrangements proposed for Dartford, the existing collective agreement between the GMB and Asda will have to be terminated.”