A good summary with links is here: https://www.the-scientist.com/features/counting-the-lives-sa...
> On a more positive note, Ferguson and other researchers at Imperial College London published a model in Nature around the same time estimating that more than 3 million deaths had been avoided in the UK as a result of the policies that were put in place.
3 million people is ~5% of the entire UK population. Even using the high end of COVID IFR estimates (2%, from northern Italy), it would have required everyone in the UK to get COVID twice with no natural immunity to reach that kind of death toll.
Also:
> The most effective measure, they found, was getting people not to travel to work, while school closures had relatively little effect.
That article appears to agree with this one.
Looks like the article on the-scientist summarized the relevant study incorrectly. The study itself posits 3.1 million deaths averted across 11 countries in Europe, not just in the UK:
> We find that across 11 countries 3.1 (2.8–3.5) million deaths have been averted owing to interventions since the beginning of the epidemic.
A bit concerning though that the second paragraph in the the-scientist article made such a significant mistake in summarizing the research.