I don't think the first issue is going to be breaking the NHS. The 10 day isolation for people "if" their symptoms are very mild or even not there is going to break a lot of things first surely? That has to be the first worry.
Then you have things like people who can't afford to not miss work still (same as before). You have people who don't want to miss their Christmas piss up or seeing their families so if they have a sniffle they aren't going to do a test.
IF it turns out that for the vast majority it is just a cold for a day then let it rip.
The problem is that if you let it rip now, and then in a few weeks time it turns out that for even a small proportion of those infected it's serious, then that small proportion will be a very large number.
By then of course, it's too late to do anything.
Here's the key point again, as made by EU scientific advisors, as opposed to UK ones (who seem to have lost your trust somewhat):
Data are currently too limited to assess the severity of disease caused by the Omicron VOC in the EU/EEA population with sufficient confidence. However, even if the severity of disease caused by the Omicron VOC is equal to or lower than the severity of the Delta VOC, the increased transmissibility and resulting exponential growth of cases will rapidly outweigh any benefits of a potentially reduced severity.
This is the key point, and it's not just Boris saying it. Link to today's full update is below:
The risk to public health posed by the spread of the Omicron VOC in the context of ongoing Delta VOC transmission in the EU/EEA is assessed in this update.
www.ecdc.europa.eu