UK scientific advisers have questioned whether a “big wave of infection” should be allowed to flow through the country’s population once the most vulnerable groups in society have been vaccinated against coronavirus, in comments which may reopen the contentious debate around herd immunity.

With prime minister Boris Johnson preparing to set out the road map for lifting England’s Covid-19 lockdown on February 22, the scientists have warned a national discussion will soon be needed on the level of risk people are prepared to accept from the virus in the future.

“There will be a massive debate about whether we should allow a big wave of infection once we’ve vaccinated all the over-50s,” one influential member of the government’s Scientific Pandemic Influenza Group on Modelling (SPI-M) told the FT. “Are we going to aim for low prevalence or accept high prevalence for a period?”