Crippling staff shortages caused by the "pingdemic" threaten to bring businesses grinding to a halt after freedom day, with one of the UK's biggest pub chains announcing closures due to absence.
When someone is pinged, they are sent an alert through the NHS Covid app telling them they have been in close contact with someone who has the virus. Therefore, they must quarantine for 10 days.
Marks & Spencer, Iceland and carmakers Nissan and Rolls-Royce are among some of the other companies who say their businesses have been hit heavily by staff having to stay off work because of the system.
On Sunday Steve Rowe, the M&S chief executive, said Covid cases at the chain were doubling every week and that changes to opening hours might be required to deal with staff shortages.
Richard Walker, managing director of Iceland, said: "We are in the unprecedented position of having to close stores due to staff absences - not because of Covid-19, but because of a broken and disruptive Track and Trace app.
"Staff absences rose by 50 per cent last week and the trend is sharp and quick, not just affecting our own colleagues but those throughout our supply chains and logistics networks."
He added: "We urgently need an overhaul of the rules around the Test and Trace app, ideally switching to a 'Test and Release' model which would come as a huge relief to employers, employees and customers and support the wider efforts to strengthen the economy."
Pressure is growing on the government to tweak the system.
On Monday the Confederation of British Industry (CBI) called on the government to immediately allow double-jabbed individuals not to self-isolate for 10 days rather than wait until 16 August.
CBI president Lord Karan Bilimoria said: "With restrictions being lifted and cases rapidly increasing, we urgently need a surefooted approach from Government, creating confidence to secure the recovery.
"This starts by immediately ending the self-isolation period of 10 days for people who are double-jabbed and providing a route out of isolation for those not yet fully vaccinated through daily lateral flow tests. Against the backdrop of crippling staff shortages, speed is of the essence.
"Mask wearing in enclosed spaces, especially transport, will help create confidence for both staff and customers, as will clarity around the future availability of free testing for employees."
Transport networks have also been hit by staff shortages and last week parts of the London Underground had to close.
The Rail, Maritime and Transport union said Saturday's closure of the Metropolitan Line due to key staff being pinged by track and trace showed how transport services were "on a knife-edge."
The union's general secretary, Mick Lynch, said: "Many rail, bus and Tube services are already seriously understaffed which leaves them dangerously exposed.
"The government's botched handling of this latest phase of the pandemic, and the rank hypocrisy of the Prime Minister and his Chancellor who don't think the isolation rules apply to them, means that their freedom day could very easily collapse into chaos day."
Despite calls for a change to the system, ministers have insisted that self-isolation rules will remain in place until 16 August.
Speaking to LBC News, business secretary Kwasi Kwarteng said that the public must remain cautious as most restrictions are lifted.
“There isn’t any movement on it,” Mr Kwarteng told the station. “It’s going to be 16th August. We’ve got to be extra cautious, so that’s why we’re going to be asking people to self-isolate until the 16th of August.”
The growing calls to change the NHS app came after England ushered in "freedom day".
Most legal restrictions on social contact have been lifted, meaning the rule of six no longer applies, large venues such as nightclubs and theatres can re-open, table service is no longer necessary in pubs and mask-wearing is now a matter of personal choice.
Professor Neil Ferguson - whose modelling led to the first lockdown in March 2020 - said Covid cases could peak at 200,000 per day after 19 July.
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