In his recent article, @cjsnowdon claims that England's November lockdown was a good example of lockdown effectiveness. Let’s look at that claim using the ONS death-by-date registration data which have now been updated for the relevant period.

Although there is some uncertainty over the average lag between infections and death, we should expect any effect of lockdown to be visible in the deaths series after about three weeks.

If the 5th November lockdown had been effective, we might expect a beneficial effect on the deaths trend from about 26 Nov and an adverse effect from about 23 Dec, reflecting the relaxation on 2 Dec.

So what actually happened?

Nationally, deaths peak on 21 Nov, 16 days after the lockdown, almost certainly too early for that to be the cause.

Deaths increase again from 4 Dec implying infections increased right in the middle of the national lockdown.

That increase may be due to the new variant, but we would still expect to see a steeper increase 3 weeks or so after lockdown was released. In fact, there is little if any clear effect on the trend.

Regional data can give more insights: LD2 should have had a bigger impact on areas not already under T2/3 restrictions: Lon, E, SE, SW.

Also, as these areas largely returned to lower tiers on 2 Dec, relaxation shd have a bigger adverse effect than in North/Mids.

What do we see?

Deaths in NW, NE & Yorks were decreasing before Lockdown 2 could have had an effect (& decreases in Yorks & NE slow soon after). EM/WM stable before & after likely impact.

Similarly no clear, consistent effect after LD2 lifted.

What about regions which should have been more affected? Still hard to see much effect at all.

Poss SE & L stabilised a little after LD but briefly. No consistent effect on trends from Dec relaxation: perhaps L accelerates a bit, but E slows down. SW little affected by either.

This is consistent with hospital admissions which should be affected some 10-12 days after LD/relaxation.

In fact admissions decreased from 12 Nov, too early for lockdown to be the cause & had started increasing again by 30 Nov, before the lockdown had even been lifted.

Given other things going on (tiers, new variant etc) we can't completely rule out some marginal effect of lockdown.

But it is hard to see much in the data to suggest England's November lockdown was effective in preventing any deaths or hospitalisations at all.