The UK's top scientists have proposed a two-week national lockdown in October to stem the recent increase in coronavirus cases, according to a newspaper report.
A second lockdown would coincide with the October half-term to create minimal disruption to schools, experts on the government's Scientific Advisory Group for Emergencies (SAGE) and the Scientific Pandemic Influenza Group on Modelling (Spi-m) have proposed.
One SAGE scientist said that if the R number continues at the same rate, it would "break the NHS", the Financial Times reports.
Responding to the report, Labour's shadow health secretary Jonathan Ashworth MP said: "Labour warned months ago that unless the government spent the summer fixing the testing regime then we would face a bleak winter.
"The government ignored that advice, the testing regime is collapsing and so it is not surprising national restrictions are back on the table.
"The Conservatives' incompetence is holding Britain back and damaging the national effort to stop the spread of this virus."
Coronavirus cases have been doubling every seven to eight days in England, according to a study by Imperial College London and Ipsos Mori.
Health Secretary Matt Hancock told the Commons on Thursday the rise in cases is "concerning", while new local restrictions are being introduced in North East England, and Lancashire is also expected to come under new measures.
The government has recently dismissed suggestions of a second national lockdown, with Boris Johnson saying it would be "disastrous" for the economy - but it appears he may be coming under increasing pressure from scientists.
A former World Health Organisation (WHO) director claimed on Wednesday that England's chief medical officer Professor Chris Whitty was recommending a two-week national lockdown.
Anthony Costello, a former director of maternal, child and adolescent health at the WHO, wrote on Twitter: "I'm hearing from a well-connected person that government now thinks, in absence of testing, there are 38,000 infections per day. Chris Whitty is advising PM for a two-week national lockdown."
But he later corrected himself, saying he had been told by another insider that Professor Whitty did not support a lockdown.
Edward Argar, a minister in the Department of Health and Social Care, told Sky News' Kay Burley: "We are guided by the science but we're not necessarily guided by the speculation in the press.
"It's not something I've heard from Chris. And it's something the prime minister clearly doesn't want to see."
The prime minister himself rubbished the prospect of a second national lockdown, telling senior MPs in the Commons on Wednesday: "We are going to do everything in our power to prevent it.
"Can we afford it? I very much doubt that the financial consequences would be anything but disastrous."
New restrictions came into force this week that forbid people from meeting in groups of more than six in England - a move designed to push down infections.
But hospitals and councils have been told to find extra beds for coronavirus patients within two weeks as the NHS prepares for a possible influx of hospital admissions, according to The Telegraph.
Isolation units are being set up where COVID-19 patients can recover and ward space will be freed up for those who need more care, the paper has reported.