Food industry employees are now allowed to do daily PCR Covid testing instead of asking staff to self-isolate.

The daily testing would be implemented at key sites, such as supermarket depots and food manufacturers, the government said. Close to 10,000 staff at 500 sites in the UK will eventually be affected.

It comes as supermarket bosses warn of severe staff shortages after thousands received alerts to self isolate.

Supermarkets said the supply of some products was being affected by the “pingdemic” keeping staff away from work, as record 618,903 people were told to self isolate by the NHS Covid app in England and Wales.

Some supermarkets downplayed fears of food shortages after some retailers said they may have to close stores,  saying the problems were not widespread.

The new daily contact testing measures are beginning at 15 supermarket depots, followed by 150 depots next week, but it will not apply to supermarket store staff.

It will mean depot workers who are alerted by the app or contacted by NHS Test and Trace will be able to continue working if they test negative, whether or not they are vaccinated.

Helen Dickinson, chief executive of the British Retail Consortium, said “disruption is limited at the moment” but it was vital that the government rolls out the scheme as fast as possible and is prepared to take further action if necessary.