Two scientists who advise the government have warned lockdown is being eased too soon in England.
Prime Minister Boris Johnson this week announced further relaxations to restrictions on movement in England, despite new coronavirus cases and deaths still being reported each day.
Professor John Edmunds and Sir Jeremy Farrar, who sit on the Scientific Advisory Group for Emergencies (SAGE), said ministers were taking risks by allowing the gradual reopening of shops and schools and larger gatherings to meet in private.
They also agreed a further risk was posed by easing the lockdown measures with an "untested" test and trace system.
Professor Edmunds said that - based on the current number of daily cases - he expected to continue to see between 40 and 80 deaths a day in England alone even without a second wave.
He said epidemiologists would prefer to see restrictions on movement continue for a longer period to prevent that happening.
"I think we are taking some risk here," Professor Edmunds told journalists.
He said this was because the sheer number of COVID-19 cases - known as the incidence - continued to stay at a relatively high level, despite the fall in the reproduction number.
Professor Edmunds said many scientists "would prefer to see the incidence driven down to lower levels, because that then means that we have fewer cases occurring before we relaxed the measures".
Yet he said the decision about where to set the number of cases was "clearly a political decision, not a scientific decision", because there was a trade-off between "the impact of the disease" and "the impact of the lockdown on wider society".
Sir Jeremy said the newly-introduced NHS test and trace system needed to be "fully working" before measures were eased.
He tweeted: "COVID-19 spreading too fast to lift lockdown in England. Agree with John & clear science advice.
"TTI (test, trace and isolate) has to be in place, fully working, capable dealing any surge immediately, locally responsive, rapid results & infection rates have to be lower. And trusted."
Although the government has focused on the reproduction number, which measures the speed of the spread of the virus, the number of cases is an equally important factor in determining the number of deaths.
The Office for National Statistics (ONS) has calculated that there are approximately 54,000 new coronavirus cases in the community in England each week, meaning there are around 8,000 new cases a day.
If the fatality rate was 1%, said Professor Edmunds, that meant 80 people would die a day.
If it was 0.5%, then 40 people would die a day.
"That's the numbers of deaths a day we might expect to see going forward," he said, adding that the true number of cases was likely higher, as the ONS did not measure cases in care homes or hospitals.
Mark Woolhouse, who sits on the government's Scientific Pandemic Influenza Group on Modelling (SPI-M) committee, warned that - because of the prevalence of the disease in the community - it would be very hard to prevent a spike in cases as people began to move around.
"A second wave is a clear and present danger," he said
As a result, he said, strong anti-coronavirus measures were a "possible new normal", adding that: "If we don't like it, going to have to find other ways of living with COVID-19."