Boris Johnson has said it remains his "ambition" to allow families to celebrate Christmas together after Labour raised the prospect of a lockdown that would effectively cancel the holiday period.
Downing Street said the Prime Minister was "hopeful" that people would be able to mark Christmas as normal, but Anneliese Dodds, the shadow chancellor, refused to rule out supporting a "circuit-breaker" lockdown over that time.
Mr Johnson's official spokesman said: "The PM has been clear previously that he is hopeful that in many ways we could be able to get some aspects of our lives back to normal by Christmas. We've been clear about the ambition to ensure that people may celebrate Christmas as a family this year."
It comes after Ms Dodds did not say whether Labour would support a "circuit-breaker" that would force people to stay at home over Christmas.
Asked about the prospect, she said: "We've always been open about this – there are always costs associated with having a 'circuit-breaker'.
"But we've got to be recognising the fact that continuing as we are with this rolling programme of original restrictions, with apparently no end in sight for many of these areas – you know, none of them have moved out for a long period from those restrictions – and that is costing our economy dear."
Meanwhile, a Government scientific adviser warned the idea that "we can carry on as we are" and have a normal Christmas "is wishful thinking in the extreme".
Professor John Edmunds, a member of the Scientific Advisory Group for Emergencies (Sage), said "radical action" would be needed to stem the rise in coronavirus cases, particularly in regions with a high incidence of the virus.
Prof Edmunds warned that a "circuit-breaker" would be needed across the country or at least in areas where Covid incidence is high, saying: "The only way that we can have a relatively safe and normal Christmas is if we take radical action now to reduce incidence – at the very least in high incidence areas – and keep the incidence low across the country by implementing a package of measures to reduce social contacts.
"The notion that we can carry on as we are and have a Christmas that we can celebrate normally with friends and family is wishful thinking in the extreme."
His comments came after the Treasury minister Steve Barclay failed to say whether families would be able to see each other during the Christmas period.
Asked how he would describe the chances of people having a "normal Christmas" despite Covid restrictions, Mr Barclay said: "The ability of families to spend Christmas together – that is something we all hope to do. All of us want to be able to enjoy Christmas with our families, and that's why there is a common purpose here to get the virus down. It is a common endeavour."
Meanwhile, as Wales entered a 17-day lockdown on Friday, the First Minister, Mark Drakeford, said the action was "about saving lives, not saving Christmas".
He added: "We think it will work in Wales to this extent. Not that it will magic the virus away, not that we will emerge on November 9 not needing to worry about it, but that it will reset the clock and allow us to get through to Christmas without needing to see a period of such significant restraint."