People across the UK will be able to meet with their families for the first time in months when the Covid restrictions will be relaxed at Christmas.
The rules mean that a number of households can mix and collect indoors for five days from December 23 to December 27.
But a top scientist has warned that the only way to make the move safe is to isolate people for 10 days before heading out to visit friends and family.
Former government chief science adviser Sir David King released the reports over alarming rates of infection among children The mirror.
The relaxation of the rules applies in every part of the UK – regardless of restrictions that would normally put an end to indoor gatherings and mixing of households.
Sir David said: “Many children will get the disease unintentionally. People will have to be extremely careful unless they isolate 10-12 days beforehand. There will be a price to be paid for Christmas. “
Professor Susan Michie of the Independent Sage scientists at University College London said: “There is a high risk if younger people are not isolated before interacting with older family members.
“When parents know there will be vulnerable people around, they should want children to isolate themselves first.”
One in five children – 900,000 – is also out of class because they have the disease or are isolated with symptoms – a 50-fold increase in September.
Prof. Stephen Reicher said Mr. Johnson should have kept the restrictions tight at Christmas. He said, “The spirit of Christmas must mean the love and strength to keep your distance.”
Prof Gabriel Scally said, “There is no doubt that Christmas will cause more cases and result in deaths.”
Peter Openshaw, professor of experimental medicine at Imperial College London, said it would be a “terrible mistake” to relax restrictions just months before vaccines “start to take effect.”
Boris Johnson has said that in the first review of the measures in mid-December, he would move areas to a level where there is “robust evidence” that the coronavirus is on a continued deterioration, and that the legislation “will disappear on February 3”.
When asked about this, Professor Openshaw said the virus should be kept under control.
He told The Andrew Marr Show on the BBC: “We scientists are indeed very concerned about the relaxation of precautions at this stage. The rates are still too high, too many cases come to hospitals, too many people die.
“And if we take the brakes off this stage, just when the end is near, I think we would make a big mistake.
“We have all sacrificed so much, everyone has sacrificed a great deal to reduce transmission speed. With just a few months to go before vaccines start to take effect, I think it would just be a terrible mistake.
“I think we have to keep this under control and just behave very, very sensibly. It’s extremely difficult to get this right and I don’t envy the politicians. “