I’ve argued throughout COVID-19 that in a pandemic compliance and non-compliance matters. The nature of non-compliance is important too. It is actually better to have a self-contained 10% of the population failing to comply if the other 90% are complying at 100%. However, if 100% of the population comply with 90% of the measures or for 90% of the time then you have a problem.
Borders matter too. Once we knew that the virus was present in the population then there was little point in imposing border quarantine controls beyond a symbolic gesture. It would have been as effective as shutting the stable door after the horse had bolted. You see, enforcing borders and boundaries is only of use if you can be certain that those borders are sealed so that either the virus is locked out of an area or locked in.
I suspect that this has been part of the challenge over the past few months. The Government introduced fairly sensible measures such as bubbles in schools and regional lockdowns (later replaced by tiers). However those measures were only as good as the boundaries around them.
Take schools for example. In Primary schools, bubbles were set up based around forms. This means that the children functioned like an extended household. They stayed together and if there was an incident of COVID then the whole class and their teacher had to stay home and self isolate. However in secondary school due to subject options, the bubbles were entire year groups meaning that the virus would have the opportunity to spread much further within the bubble. Schools might try to identify those that had been in closest contact but meanwhile those people will already have been in contact with others. At the same time, all of the attempts to keep year groups apart in school would have been pointless when the children intermingled across year groups at home time. The bubbles were too large and their borders were too porous.
The same problem applied to regional lockdowns and tiering. Often a lockdown would be applied to a whole region despite COVID rates being dramatically different council ward to council ward and even neighbourhood to neighbourhood. This created resentment in areas where strict measures were imposed despite virus rates being low. Meanwhile, people were able to move in and out of lockdown areas freely. The ridiculousness of this became obvious when London was put into a much lower tier than its surrounding commuter belt. A local or regional lockdown only makes sense if people are quarantined within that region or neighbourhood as happened in Wuhan at the start. The aim is to ensure that the virus is suppressed long enough to prevent it from spreading.
If you want to prevent a virus spreading, then you have to ensure that its carriers are prevented from moving about to stop its transmission.