When NHS Test and Trace was launched on May 28 last year, it was hailed alongside the vaccination programme as one of the weapons to bring an end to the Covid pandemic and return Britain to normality.
But 14 months on, the system has plunged the country into the very chaos it was supposed to alleviate, creating a "pingdemic" that could bring the economy to its knees.
With more than more than 530,000 people "pinged" by the NHS app in England and Wales during the first week of July and advised to remain in self-isolation for up to 10 days after coming into contact with someone who has tested positive for Covid, there is the real prospect of industry and services grinding to a halt.
There are warnings of every sector, from transport to production and retail, running short of workers this weekend.
Number of contact tracing alerts sent in England
Heathrow has said more than one million holidaymakers face chaos in August if ministers refuse to extend a pilot scheme allowing staff to go to work if they test negative for Covid.
Bosses at the airport have written to the Government, pleading with ministers to allow the trial to be extended or risk a repeat of queues as long as six hours experienced earlier this year.
Next month is typically Heathrow’s busiest as families head for some summer sun. The airport welcomed more than 7.5 million people in August 2019 and 1.4 million in the same month last year despite Covid border restrictions.
Heathrow said the testing pilot had been vital in keeping the UK’s largest port open, and a spokesman added: "Failure to take this practical step would not only undermine the Government’s objective to get on with managing the virus instead of letting it managing us but also risks creating significant disruption for passengers and trade through the UK’s hub airport, pushing Britain further behind its European competitors."
Rail bosses warned there could be disruption and cancellations on Monday due to train drivers and staff being pinged en masse by the app. Train operators are braced for a surge in commuters heading back to the office as the Government’s working from home advice officially ends.
However, rail industry sources told The Telegraph that losing staff to app notifications was becoming an "increasing problem" for companies and leading to services being cancelled at short notice.
On Saturday, Northern warned passengers not to attempt to travel between Sheffield and York after a slew of services were axed because the staff were not available to run them. A senior rail source said operators were preparing to ask staff to work extra hours or swap shifts to prevent trains being cancelled during peak times from Monday.
On Saturday, London Underground suspended the Metropolitan Line due to a staff shortage triggered by workers told to self-isolate. Services on the Piccadilly and District line were also affected.
This weekend, Robert Nisbet, the director of nations and regions at the Rail Delivery Group, which represents the UK’s train operators, warned commuters to check their service was still running before heading to work on Monday.
He said: "As Covid cases increase, more rail employees could be pinged by the NHS contact tracing app and be asked to self-isolate. While train companies are doing everything they can to minimise any disruption, there may be an impact on services."
The first indication that the economy was vulnerable to the "pingdemic" came on Tuesday, when it emerged that hundreds of workers at Nissan’s 6,000-strong Sunderland plant were self-isolating after coming into contact with someone with the virus. Due to the high numbers, the company has had to make changes to how the factory is run.
The next day, Rolls Royce warned that it was "approaching a critical point" due to workers having to self-isolate and said it may have to halve production if the trend continued. The company said it was "extremely concerned" at the number of staff at its manufacturing site in Goodwood, West Sussex, being told to stay at home by NHS Test and Trace alerts.
That evening, Stephen Phipson, the chief executive of manufacturers’ association Make UK, told Sky News that there had been a "very significant rise" in the number of workers in the sector being required to stay at home over the past 10 days. He added that in many companies it had resulted in one in five people being off.
Steve Turner, the Unite assistant general secretary, joined the chorus of warnings, saying: "No one is advocating for coronavirus controls to go out the window, and Unite’s number one priority remains the health and safety of our members.
"But the reports Unite is receiving from our members and their employers are extremely worrying. It is not an exaggeration to say factories are on the verge of shutting, and that at some sites hundreds of staff are off work."
Mr Turner warned that people would simply start deleting the NHS app if a solution was not found soon.
The same day, Lord Bilimoria, the president of the CBI employers’ group which represents 190,000 businesses, said: "Staff shortages are being felt acutely across all sectors and in all areas of business, particularly hospitality and leisure."
He called for an "overhaul" of the NHS Test and Trace system, saying the Government "urgently" needed to bring forward its plans to allow double-jabbed individuals not to self-isolate.
The hospitality sector warned that pubs and restaurants would have to close their doors because of the level of pings being received by staff.
NHS Covid app venue alerts sent
Kate Nicholls, chief executive of UKHospitality, said the industry was facing "significant staffing challenges", with up to a fifth of staff isolating at any one time.
"Without better intervention, operators will continue to be forced to reduce their operating hours or to close venues completely, missing the opportunity to begin on their road to recovery," she said. "We urge the Government to move quicker on this issue to prevent the summer being cancelled and vast swathes of the population unnecessarily confined to their homes."
Speaking from the Cinnamon Cafe she runs in Ealing, west London, Rachael Hunt said: "I’m one of the lucky ones – none of my staff have been pinged so far. But if my staff got pinged, I’d have to shut down."
It was a prediction echoed across the small retail sector.
Andrew Goodacre, chief executive of the British Independent Retailers Association, said: "In a small shop, if one member of staff tests positive it’s likely that nearly all that team will be deemed to be in close contact, including the owner. Most likely, the shop has to close. That’s a tragedy when they’re just in the process of rebuilding their business."
By Friday, there were warnings that consumers could see shortages of some foods if firms do not have enough staff to carry out key functions.
The Meat Processors Association (MPA) said abattoirs would have to "rationalise" product lines, stopping those requiring the most butchery, in order to keep food on shelves.
The "pingdemic" could not have come at a worst time, just as England prepares for the lifting of all legally-binding social distancing restrictions on Monday – so-called "Freedom Day".
Scientists have warned that the move is a huge gamble, and the reopening of pubs, restaurants, cinemas and theatres has already fuelled the surge in numbers being advised to self-isolate. With more people going out – especially young people who have not yet received both vaccinations – cases of contact with infected individuals have rocketed.
The gradual reopening, along with the new, more infectious delta virus variant, has already led to a dramatic increase in infections, rising to a daily total of 51,870 on Friday and a weekly total of 277,995 – a seven-day increase of 34.9 per cent.
Where is the Indian (Delta) variant in the UK?
But help is on the way. Fully-vaccinated individuals in England will be exempt from having to quarantine following close contact with people suffering Covid. But this change will not be introduced until mid-August – far too late, say critics, not to cause lasting damage to the economy.
One senior business source told The Telegraph: "There are a number of things the Government needs to do really urgently, such as amending self-isolation rules – which has got to happen sooner rather than later.
"It is pretty frustrating for businesses, especially those in retail, hospitality and leisure, which have been hardest hit during the pandemic but now find themselves having to deal with staff shortages that means they cannot contribute as meaningfully as they could towards securing the economic recovery.
"The Government has to change the rules, and they may want to think about allowing people who are double vaccinated and can prove they are not positive that they should not have to self-isolate. Then for the people not double vaccinated, such as young people who work in hospitality and leisure who have been hit hardest by this, they need some sort of test and release mechanism."
Mike Cherry, the chairman of the Federation of Small Businesses, said: "The Government should explain, in detail, the reasons for ending self-isolation rules for the double vaccinated on August 16 rather than on Monday and investigate whether there is scope to safely bring that key moment forward.
"As things stand, we could end up with a scenario where trade is restricted now, putting the brakes on a summer boom, only for self-isolation rules to end further down the line when cases are even higher."