Looking at the daily report stats for today, there seems to be a very clear correlation in case numbers increasing and testing increasing. It also looks like testing has shot up since Omicron was revealed. Therefore I wouldn't be surprised if the positivity rate is very similar. Of course what we should be focusing on is hospitalisations and deaths, which have been taking much longer to react to rising cases, which implies boosters are working, and/or infections are milder overall (note this must be a very rare, even maybe the first time, that a metric has had "NO CHANGE" for the last 7 days):
Showing public health data across England
coronavirus.data.gov.uk
We're also at 22.18m booster shots so far, going up around 300-500k per day, which doesn't scream concern.
I think the most likely outcome is that Boris Johnson would no longer be PM. Given how many Tory MPs are clearly against Plan B, implementing a lockdown would tip many MPs over the edge so to speak. I think there would be a leadership challenge that he would lose. This would make any future PM, particularly if they are Tory PM, far more weary of implementing restrictions in the future.
If further measures being touted in tomorrow's papers as under consideration are brought in before the retrospective vote for Plan B on Tuesday, or even shortly after, Johnson will be in even more serious trouble than he already is, as not only are there many backbenchers against Plan B, but even those hesitantly in favour of it will not like having further restrictions brought in before they've even voted on the previous round of them. As for a future leadership challenge, I would expect many MPs against restrictions will only support a candidate who is very clearly against restrictions, such that it's possible a CRG member will stand if a challenge was nigh in the hope of automatically getting support of the rest of the CRG.
We're also now at the limit more or less of where furlough wouldn't be necessary to compensate restrictions. Anything else imposed will either see furlough return, to the disgust of many Tory MPs against such a socialist policy, or businesses and jobs left for dead without furlough support would hit the economy and unemployment even more, which looks very bad publicly, reduces Tory support further, disgusting Tory MPs also.