Asda’s owners have revealed a planned shake-up that places hundreds of jobs at risk and will see thousands moved to lower-paid roles.

The company has proposed that some overnight restocking shifts at 184 stores are moved to the daytime, putting 211 night shift manager roles at risk.

Asda said the changes would also affect 4,137 hourly-paid workers as their shift patterns would also move to the daytime, resulting in the loss of their night shift pay premium of at least £2.52 per hour for restocking goods such as frozen food, tins and pasta.

The plans would also see the opening hours for 23 in-store Post Office branches cut by a quarter and seven in-store pharmacies, which employ 14 pharmacists and 48 other workers, closed down.

The UK’s third-largest grocery chain by market share said its changes were the result of an “efficiency” drive but they were met with stinging criticism by the GMB union.

The shake-up comes at a time when supermarket profitability has been squeezed by the need to cut prices and compete as discounters Aldi and Lidl continue to eat away at the established grocers’ customer bases amid the cost of living crisis.