Schools are closed. Construction is largely closed. People have time off work booked.
Just get EVERYONE who doesn't need to to stay at home for two weeks and massively reduce transmission.
More people than any other fie of the year are off anyway.
Get it under control (quarantine everyone coming into the country as well) and then see where things are in mid January.
I post this from a hotel bar getting ready for a Christmas do with 350 people because that's what we did in April. I get the UK is a big place, but if EVERYONE did the right thing for two weeks (Road blocks and the works) it would surely lead to a massive decrease in transmission