Any pre Christmas circuit breaker would have been widely ignored , mainly due to the recent revelations.
Everyone is entitled to an opinion of course, but, last years Circuit breaker, in England, was widely ignored, in my experience, even before "party-gate".
The devolved Governments (Scotland and Wales) have had more strict "rules" and restrictions, than England, including "circuit breakers" at various times, during the past two years.
Are Wales and/or Scotland in a significantly "better" situation, Covid wise, than England?
Of course, it is quite possible that compliance, in Scotland and Wales has been no better than in England (even before "party-gate").