Could Boris Johnson and Rishi Sunak have avoided the need to self-isolate for 10 days despite being contacts of the health secretary, Sajid Javid, who tested positive for Covid-19? On Sunday morning, Downing Street claimed they were due to be part of a workplace pilot scheme trialling tests instead of isolation. However, an abrupt U-turn in the face of public anger means the prime minister and chancellor will now self-isolate. What pilot scheme is Downing Street enrolled in? Ministers have claimed they are part of a “workplace testing” scheme involving 20 public bodies that have set up asymptomatic testing sites. Individuals from those organisations who have had contact with someone who has tested positive for Covid can go to work on the basis that they are using lateral flow tests, but must self-isolate when not at work. How can someone join the scheme, and who has benefited? According to the communities secretary, Robert Jenrick, organisations on the scheme include government departments, Transport for London, Network Rail and Border Force. But a spokesperson for TfL has denied being part of the scheme, saying the organisation is still waiting to join. The RMT union has claimed that no such scheme has been set up in Network Rail or TfL. Border Force sources claim a pilot scheme has been set up at offices in Manchester and Dover but say it is under review because it has proved to be unpopular with staff. Downing Street did not divulge the other bodies taking part as they had not given consent, but a spokesperson claimed a full list would be published after results were in. Jenrick described the scheme as “well-known and longstanding” although there is no obvious mention of the scheme online. Downing Street insists it is “totally separate” from another project, the “daily contact testing study”, which was set up in May and splits participants at random into two groups. One cohort, a control group, has to self-isolate, while the other – numbering up to 40,000 people when the pilot was established – takes daily rapid tests. The Cabinet Office minister, Michael Gove, benefited after being “pinged” by the Covid-19 app after a trip to Portugal for the Champions League final in May. He went on to and then came off the pilot scheme in May, a source close to the minister said. When is it necessary to self-isolate? In England, it is a legal requirement to self-isolate if you are identified as a contact and told to self-isolate by NHS test and trace. Those who are “pinged” by the app as a contact of another user who has tested positive for Covid-19 are “advised” – but not legally obliged – to isolate for 10 days. Separate guidance is in place for health and social care workers. Those providing direct care to a patient or a resident with Covid, and who have been wearing the correct PPE, are not considered to be a contact for the purposes of contact tracing and isolation. The government has been coming under pressure to make more key workers, including those in meat-processing plants, exempt from isolation after contact with a Covid case. From 16 August, double-vaccinated people who have had their second jab at least two weeks earlier and under-18s in England will not have to isolate. Who is bearing the brunt of directions to self-isolate? Up to 1.6 million people were told to isolate in a single week, Guardian analysis found, including more than 520,000 contacted by the Covid-19 app – up 46% in a week. But the government said the app was likely to remain unchanged for weeks. Rubbish bins in parts of England are going uncollected, West End theatre shows have been cancelled and some health workers have been urged to postpone holidays because of staff shortages. The situation, branded a “pingdemic”, has led to demands from industry leaders for help amid widespread staff shortages as workers are forced to isolate en masse. Soaring cases are responsible, with more than one in 100 people in England estimated to have Covid, and the situation is expected to worsen after further reopening on Monday. Test and trace does not yet take account of vaccination status.