The UK is “at a dangerous moment” and the easing of lockdown “has to go slowly” England’s deputy chief medical officer has said.
Prof Jonathan Van-Tam said the consensus among scientists was that the new measures were not expected to push the rate of infection above 1.0.
However, he cautioned the public to be “sensible and proportionate with the freedom we have wanted to give people”.
“Don’t tear the pants out of it,” he told the daily Downing Street briefing.
It comes as scientific advisers to the government warned of the risk of lifting the lockdown in England.
From Monday schools will reopen and up to six people can meet in England, with other nations also easing measures.
Professor John Edmunds, a member of Sage – the Scientific Advisory Group for Emergencies which advises the government – said the levels of coronavirus were still “very high”, adding that it was a “political decision” to ease measures.
Estimates by the Office for National Statistics suggest there are currently 8,000 cases per day in England alone.
Fellow Sage member Sir Jeremy Farrar said the NHS test and trace system should be “fully working” before measures were introduced.
Two further members of Sage, Professors Peter Horby and Calum Semple, also spoke out about the relaxation of lockdown measures, suggesting it was still “too early”.
Culture Secretary Oliver Dowden, who led the briefing on Saturday, said scientists were “absolutely right to urge caution”.
He said it was a risky moment, but described the measures agreed so far as baby steps.
“At each stage, we are not going to proceed unless we are confident that we can do so in a safe way,” he said.
He added that there were more than 50 scientists in Sage “all of whom will have their different perspectives” and the government takes a “collective view”.
A further 215 people across the UK who tested positive for coronavirus have now died, taking the total death toll to 38,376.
Prof Van-Tam told the press conference that the lockdown easing must go “painstakingly” slowly, adding: “The scientists will continue to give that advice to the government. No apologies for that – we will absolutely continue to do that.”
“I believe this is also a very dangerous moment. We have to get this right.”
He said Sage was clear that the chances of the new measures allowing the infection rate – R – to go above 1.0 were slim “with good compliance and the test and tracing system in place”.
“Our science advice has been – so far – that the social distancing that has already been eased is consistent with keeping the R below one.”
But he stressed the “dual responsibility” of the government and the public, whom he urged not to “go further than the guidance actually says”.
It comes as the culture secretary announced that competitive sport will be allowed behind closed doors in England from 1 June, paving the way for the first live action in almost three months.
“The British sporting recovery has begun,” Mr Dowden told the briefing. “Football, tennis, horse racing, Formula One, cricket, golf, rugby, snooker and others are all set to return to our screens shortly.”
It was also announced that people in England will be able to exercise outside with up to five others from different households from Monday