Wales has delayed the reopening of schools in January, while leaders in Northern Ireland are considering tougher measures after Christmas, as Omicron cases continue to surge across the UK.
In England, Boris Johnson has urged people to “think carefully” before socialising this Christmas.
“We’re not cancelling events, we’re not closing hospitality, we’re not cancelling people’s parties or their ability to mix,” he said.
“What we are saying is think carefully before you go. What kind of event is it? Are you likely to meet people who are vulnerable, are you going to meet loads of people you haven’t met before? And get a test.”
Cases of Omicron are surging across the UK, with daily confirmed Covid-19 cases reaching a record high of 78,610 new cases on Wednesday.
At a Downing Street press conference last night, chief medical officer Professor Chris Whitty warned that “records will be broken a lot over the next few weeks”.
He said people should weigh up whether to risk mixing with others or cancel their plans to improve the chances of spending Christmas with their families.
Prof Whitty told the public “don’t mix with people you don’t have to” at events that are not among the most important to them.
Mr Johnson declined to go as far as Scotland’s First Minister Nicola Sturgeon, who has given specific guidance to urge people to limit their socialising to three households around Christmas.
Professor Sir David Spiegelhalter, who advises the government on the Scientific Advisory Group for Emergencies (Sage), said it is possible that a million people could be isolating with Covid infections on Christmas Day.
Downing Street has said there are no plans to bring in further restrictions ahead of Christmas Day.
Weekly infections up 8.7 per cent in England, according to latest figures
A total of 315,001 people tested positive for Covid-19 in England at least once in the week to December 8, up 8.7 per cent on the previous week, according to the latest Test and Trace figures.
This is the highest number to test positive since the week to January 13.