Union leaders have launched a battle against Government plans to end the pingdemic in a move that threatens a summer of disruption for holidaymakers, shoppers and commuters.

Critical workers are able to avoid self isolation via a Government scheme launched amid fears key infrastructure could collapse under the pressure of hundreds of thousands being told to stay at home by the NHS app.

However, leaders of the UK’s largest unions are now encouraging key workers, including in transport and food, to ignore the exemption and stay at home, citing fears that they could be exposed to Covid-19 in the workplace, the Telegraph can reveal.

The move risks causing chaos at airports as the summer holidays begin, with a minister already forced to apologise for delays at the border which he blamed on the pingdemic.

Steve Hedley, senior assistant general secretary of the RMT, threatened to launch strike action over Downing Street’s exemption scheme.

The Government are ‘panicking’ 

“Why should our people be infected with Covid? They are panicking and trying to force our workers back to work, where it’s not safe,” Mr Hedley told the Telegraph.

“We have discussed the possibility of taking action at a senior level, and I can say that nothing has been ruled out.”

Ministers will on Monday discuss the growing chaos across the UK’s critical infrastructure at a meeting of Covid-O, the sub committee of the Cabinet which deals with pandemic operations.

During another Covid-O meeting last Thursday, officials are understood to have warned that passengers face three-hour airport queues due to a critical shortage of Border Force staff.

Border Force problems

However, the exemption scheme is unlikely to ease the disruption, as the union representing Border Force officials last night suggested it was "unworkable” and that members were reluctant to take part.

Lucy Moreton, professional officer for the ISU union, said: “I am not sure how you would enforce it. You cannot compel them to test. Equally, I am not convinced Border Force can compel employees to say if they are double vaccinated.”

Ms Moreton said Border Force officers often work four shifts in a 10 day period, so would refuse to travel to testing sites on their days off without being paid.

“Border Force staff count their time very carefully because they are used to accounting for it in chunks,” she said.

She said that when Border Force officers had the option to take part in an earlier pilot to avoid self isolation, they had not done so.

Sources warned that increasing numbers of Border Force officers were self isolating, either because of being pinged or contracting the virus.

Are you exempt?

Last week, nearly a quarter (108) of the 450 staff at Heathrow were off, while at Manchester on one day last week it was 31 out of about 200. At Bristol, it was nearly half, 12 out of 28. Many officers have also been deployed to Dover to help their colleagues cope with the Channel migrants crisis, sources said.

The impact of the staff shortage is likely to become even more acute on Aug 1, when thousands of expats jabbed abroad are set to be invited to return to the UK without quarantining.

Kit Malthouse ‘sorry’ for inconvenience 

Kit Malthouse, the policing minister, has apologised for delays at the borders as families set off on the first weekend of the summer holidays, which were branded "total chaos" by travellers.

“I’m sorry for the people that were inconvenienced,” he said. "Hopefully Border Force will be relieved of some of the aspects of the pingdemic."

Last week, Downing Street drew up a list of critical workers who could apply to avoid self-isolation after more than 600,000 people were pinged in a single week by the NHS Test and Trace App.

The scheme was then expanded to allow entire sites, such as food distribution centres, to be exempt by setting up testing hubs. It was initially just for those working in food production, but was widened on Friday to cover transport and freight workers, frontline police and fire services and border officials.

Ministers are now proposing to expand the number of designated testing sites for Border Force officers beyond the current two in Manchester and Kent, Whitehall sources said.

Ministers included food supply workers on the list of exemptions after supermarkets ran out of basic supplies in some areas.

Over half a million ‘pinged’ at start of July

But Paddy Lillis, general secretary of Usdaw, which represents workers in retail, distribution and food manufacturing, said staff would be backed to stay at home rather than return to work.

“Usdaw remains clear that employers should support staff, in line with public health guidance, if they are advised or required to self-isolate,” he told The Telegraph.

“Usdaw does not believe that the current situation in the food supply chain is critical or warrants the sector being placed on the exemption list.”

Last week Christina McAnea, the general secretary of Unison, which has 1.4 million members mainly working in the public sector, told The Telegraph: "Anyone pinged or called by Test and Trace should isolate. Staying at home protects colleagues, neighbours, friends and everyone else too.

"No one should be forced into work when isolating, even those employees on the exempt list."

A Government source said: "We are trying to make it as easy as possible to protect public health which is why we have set up pilots and testing sites. We want to ensure there are as few queues at the border as possible and that means people doing the right thing and getting tested to protect public health."