Up to half a million people in Liverpool are set to be tested for Covid-19 under the UK government’s first attempt to embark on city-wide mass testing and track down every case of the virus. The Guardian also understands that the self-isolation period for those who test positive for coronavirus, and their contacts, could be cut from the current 14-day period to seven days as early as this week. It comes after ministers, who announced a new England-wide lockdown from Thursday amid soaring cases, face pressure to improve the beleaguered £12bn test-and-test trace system to control outbreaks and limit the lockdown to four weeks. Under the Liverpool mass testing programme, which begins on Friday and will cover everyone living and working in the city, a variety of test types and the logistical help of the army will be deployed in a pilot to see whether mass population screening is feasible across other regions of England, as proposed in Operation Moonshot. To be successful, it will need not only to find those who are infected regardless of symptoms, but convince them to self-isolate. Only 20% to 25% of people are estimated to quarantine fully when asked to do so by test and trace. With that in mind, the government is also pushing forward with plans to cut the self-isolation period. It is understood to be preparing to make changes this week, including potentially halving the 14-day timeframe. The move comes amid rising concerns in Downing Street about compliance with the new lockdown rules and instructions to quarantine. “Those who have been contacted need to self-isolate,” Johnson told MPs in the Commons on Wednesday. “We’ll be making a big, big push on that. Because, I must be candid with the house, alas the proportion of people who are self-isolating in response to the urges of NHS test and trace is not yet high enough.” An all-out effort to get as many people tested as possible in Liverpool – one of the country’s worst-hit areas with weekly Covid cases of 410 in every 100,000 last week – will depend on people’s willingness to come forward. Testing of the 500,000-strong population will be carried out in new and existing sites, using home kits, in hospitals and care home settings, and in schools, universities and workplaces. Some will be invited for tests but walk-up and online bookings will also be possible, and 2,000 army personnel will be involved. The tests will include rapid lateral-flow tests that can use nose-and-mouth swabs or saliva and produce results in 15 minutes, as well as the more reliable PCR tests, which are designed to return results within 24 hours – although this turnaround time is often doubled. “LAMP” technology will be used in Liverpool university hospitals NHS foundation trust for testing NHS staff. People who test positive will receive a text or email from NHS test-and-trace staff and will be asked to self-isolate and share details of close contacts. The Department for Health and Social Care says the pilot will help inform a mass testing blueprint and demonstrate how fast and reliable Covid-19 testing can be delivered at scale. Johnson thanked the people of Liverpool in anticipation of the programme. “These tests will help identify the many thousands of people in the city who don’t have symptoms but can still infect others without knowing. Dependent on their success in Liverpool, we will aim to distribute millions of these new rapid tests between now and Christmas and empower local communities to use them to drive down transmission in their areas,” he said. “It is early days, but this kind of mass testing has the potential to be a powerful new weapon in our fight against Covid-19.” Liverpool city council will let people know how to access tests this week. Joe Anderson, the Labour mayor of Liverpool, said: “During negotiations with central government, myself and Steve Rotheram [the regional mayor] have always highlighted the need for enhanced public health intervention measures in Liverpool and the wider city region, and we were keen that we should be considered for any new strategies to tackle the worrying rise in Covid-19.” The first successful example of mass testing was in Vo in Italy. When the country’s northern region was struggling with the earliest deadly outbreak of Covid-19 in Europe, the small town near Venice tested all its 3,000 inhabitants, whether or not they had symptoms. On 6 March, when the programme began, there were no rapid tests. The University of Padua and the Red Cross who jointly carried it out used PCR swab test. They picked up even asymptomatic people and all those with a positive test were quarantined. The first round of testing picked up 89 people with infection. A second round nine days later found six. In 14 days, they had eradicated the virus. The scientists who masterminded it recommended the approach to the UK at the time. What is feasible in a small community gets harder the larger the population. Slovakia’s decision to test its entire population of 5.4 million is considered hugely ambitious but on Monday it was reported that two-thirds had been tested, with 38,359 people, or 1.06%, found to be Covid-positive. Slovakia is the biggest country so far to embark on mass testing of the population. Luxembourg, which is smaller, has done it and so have some Chinese cities with larger populations than Slovakia, such as Wuhan where the coronavirus first appeared.