problem is that's too late, for pretty much anything christmas related.
go into a proper form of lockdown, and the challenge will be that infection rates, confirmed cases, and deaths are unlikely to be falling/have fallen sufficiently.
Others have said earlier, a strict 2-3 week lockdown at some point during the past 3-5 weeks would likely have reduced the infection rate sufficiently to facilitate some relaxations over christmas.
These lot have prevaricated too much. A populist government isn't going to want to make harsh or difficult decisions, so as a result, no decisions have been made. As a result, all the numbers are going the wrong way.
One option might be to close schools earlier, and move all university teaching etc to online only from 1 december (as worth remembering that there are 2.5 million people likely to want to return home for the christmas period, and that is going to need managing. I can see the government at a very late stage telling students not to return home. They won't follow that advice, I see regular cases of students moving back home as things stand.)
The most likely consequence I can see, is a much longer lockdown from early january onwards, possibly lasting 2+ months, with the government blaming the population for the high number of cases/deaths, because we all mingled too much and visited each other over christmas. I feel a lot of people are going to see other family members over christmas tbh. I just hope many of them isolate for a couple of weeks prior if they can.