Both the King's College and the ONS data are both showing a plateau in new infections.
covid.joinzoe.com/post/over-the-second-wave
www.bbc.co.uk/news/health-54841375
It does beg the question, if the Tier system was working, why lockdown? I suspect the answer is political and to stop the North (Red Wall) where immunity is/was lower feeling targetted by level 3 restrictions.