The PM announced on Tuesday that three households will be able to mix in a bubble from December 23 to 27.
Johnson said the agreement between his government and devolved administrations meant families would be able to come together across the UK, but added: “The virus doesn’t know it’s Christmas and we must all be careful.”
Reacting to the news, a member of the government’s Scientific Advisory Group for Emergencies (Sage) warned last night the planned relaxed restrictions could lead to a third wave of the pandemic.
Professor Andrew Hayward told BBC2’s Newsnight: “Effectively what this will be doing is throwing fuel on the Covid fire.
“I think it will definitely lead to increased transmission. It is likely to lead to a third wave of infection, with hospitals being overrun, and more unnecessary deaths.
“We are still in a country where we have got high levels of infection with Covid, particularly in young people. Bringing them together for hours, let alone days, with elderly relatives, I think, is a recipe for regret for many families.”
Hayward added that with vaccines on the way “we are really in danger of snatching defeat from the jaws of victory on this one”.
The sentiments were echoed by colleagues in the scientific community. Professor Graham Medley, an expert in infectious disease modelling at the London School of Hygiene and Tropical Medicine, said the move could lead to more people being admitted to hospital and further lockdown measures in the New Year.
The Sage attendee told BBC Radio 4’s Today programme: “I think we’re in a process now whereby the population’s risk of filling up the NHS is really being passed down to us as individuals.
“For other diseases like flu or hepatitis B, the government doesn’t get involved in helping or determining what our...