I think this may be more realistic than people might be suggesting.
We ALREADY know that universities are to be staggered back.
And the christmas restriction guidance has been updated. I don't believe this was stressed in the earlier press conference this afternoon but it says:
From 28 December
It is important to cut down on social contact after seeing your Christmas bubble, to reduce the risk of chains of transmission. From 28 December, you must follow the guidance for the tier in your area, as a minimum. Christmas bubbles will no longer apply. In most places across the UK, that means you cannot mix with other households indoors, including on New Years’ Eve.
Those who choose to form a Christmas bubble should exercise additional caution and cut down on unnecessary social contact after seeing their Christmas bubble to reduce the risk of spreading the virus. This includes not meeting up with friends or family outside your household for New Years Eve.
Note this is aimed both at people who bubble up AND people who don't.
I therefore don't rule out a mini lockdown in the days after the 27th being put in... And starting schools back later or via online for a week, wouldn't be that out there in that context either.