Boris Johnson returned to Downing Street on Sunday night with his government under pressure over its handling of coronavirus, as ministers warned that physical distancing must become the “new normal” – even when the lockdown is eased. With the prime minister pressed to explain how schools and businesses can reopen without putting lives at risk, the government has given the clearest signal yet of how it hopes to manage the next phase of the pandemic, including imposing quarantine restrictions on all arrivals at UK airports. Hospital deaths from the virus announced on Sunday were 413, taking the total to 20,732. That was the lowest daily total since the end of March, though is expected to increase again during the week. Dominic Raab, who has been deputising since Johnson was taken into hospital with Covid-19 at the start of the month, said on Sunday it was inconceivable that children could return to school, without “further measures” to check the spread of the virus. He also suggested businesses hoping to return to work in what he called the “second phase” of the crisis would have to learn from the essential shops and other workplaces that have remained open, giving the example of distanced queues outside supermarkets. “There are all sorts of precautions that businesses have taken. If you think that those are the measures that we’ve taken for essential businesses that haven’t shut down, you can see how in various different ways they could be expanded to non-essential businesses currently closed,” he told the BBC’s Andrew Marr. “We won’t just have this binary easing up of measures. We will end up moving to a new normal.” Johnson, who has been easing his way back into work with video conference calls, and a three-hour meeting with key ministers at Chequers on Friday, will be back at his desk in No 10, amid growing pressure from some in his own party to lift restrictions. Raab said Johnson would be “back at work full-time, properly, at the helm” and is “raring to go”. The lockdown measures, imposed on 23 March, are due to be formally reviewed by 7 May. The prime minister’s personal role in the earlier stage of managing the outbreak has come under criticism in his absence, while the government has been under relentless pressure over the lack of PPE for frontline health workers, and the shortfall in testing. Matt Hancock, the health secretary, finally announced last week that he will seek 18,000 volunteers to track and trace Covid-19 cases. Labour has been calling for contact-tracing for weeks, as have public health experts and Hancock’s predecessor Jeremy Hunt. Health checks and quarantine restrictions for passengers arriving at airports have also been implemented by many other countries. Confirming the government is now considering such measures, Raab insisted that medical advice had previously suggested this would not be effective while the virus was freely circulating within the UK. In a letter to Johnson at the weekend, the Labour leader, Sir Keir Starmer, said: “I fear we are falling behind the rest of the world.” The chancellor, Rishi Sunak, will underline the costs of shuttering the economy to tackle the crisis on Monday, as he makes a statement to the House of Commons on the Treasury’s response to the crisis. He will point to forecasts by the independent Office for Budget Responsibility that suggested a three-month lockdown could lead to a catastrophic 35% decline in GDP in the second quarter of the year. Sunak is among those cabinet ministers who have been keen to see some businesses reopen, and officials have been working on proposals for deciding which should come first – based on how easy it would be for them to work safely, and how critical they are to the economy. Raab is cautious about lifting restrictions too soon, however, and during several interviews on Sunday, repeatedly stressed the risks of avoiding a second peak in infections, which he said would damage the economy, as well as public health. “We’ve got to make sure of two things: first of all we don’t risk a second spike, for all the reasons we’ve discussed. Secondly, that overall this package doesn’t allow the coronavirus to get back hold, to spread more widely and to undo all the progress we’ve made, or the sacrifices so many people have made,” he said. He also echoed the warning of Prof Chris Whitty, the chief medical officer, that a vaccine is unlikely to be widely available this year. The TUC is calling for businesses to be obliged to make a comprehensive risk assessment before they can reopen. “We need tough new measures from government to reassure working people that their health and safety is a priority” said its general secretary, Frances O’Grady. “Too many workers have already been forced to put their health on the line during this pandemic. “We all want everyone to get back to work and start rebuilding Britain. But workers need confidence that they won’t have to put themselves or their families at unnecessary risk.” Polling carried out for the TUC showed 40% of workers are concerned about the health risks of returning to their workplace. O’Grady called for bosses who put the health of their staff at risk to be prosecuted. Raab declined to say what physical distancing in schools might mean in practice – though Nicola Sturgeon, the Scottish first minister, suggested that in Scotland it could involve staggered attendance by different year groups. “It would not be right or safe to open schools right now and that may continue to be the case for some time to come, but the point I think everybody is trying to get their heads round right now is that as we come out of these very restrictive measures we’re not going to be going back to normality as we knew it,” Sturgeon told Marr. “It’s what I described – and many others have used this phrase – a new normal that we’re looking for where social distancing will be a fact of life for quite some time to come and different ways of operating will have to be contemplated.” The shadow education secretary, Rebecca Long-Bailey, called the government to consult with the teaching unions about how best to manage children’s return to school when it is safe to do so. “School leaders, teachers and support staff have been working tirelessly to keep children’s education going during this crisis and to minimise disruption and the inevitable impact on social inequality. Any decision to lift restrictions cannot be sprung upon schools at short notice,” she said. In another sign of the scale of disruption to normal life, the environment secretary, George Eustice, repeated his call for furloughed workers to go to the aid of Britain’s farmers, by picking fruit and vegetables during the harvest season this summer.