He had the disease - so thought he was immune.
But that was a mistake - we have repeatedly been told that it is not 100% conclusive that if you have coronavirus, you will be immune. It is too recent a virus to be able to reach that degree of certainty. He should have known this even though he is a mathematician, not a virologist.
The Conversation article I posted upthread said exactly the same as BigChocFrenzy, namely that models are only models. That is why we still do expensive community prevalence studies.
I think it was the Business Insider article that mentioned that Ferguson had not shared all his code. I think that is concerning, but of course there are intellectual property and commercial factors to bear in mind with this sort of research.
There was a fair amount of voluntary social distancing before lockdown. I was astonished at how empty London was on my last trip into the office (which was for a meeting arranged ages beforehand). There was also a huge clamour to close schools. At the same time, the last few days were quite chaotic - full pubs in the evenings, empty offices in the daytime, people driving around desperately trying to find supermarkets that were not empty. We are a much less compliant society than Sweden. That’s apart from all the other differences like population density, proportion of one person households and a higher prevalence of home working.
I don’t like the way some people think this news is to distract us from the death rates here, as if we can only hold one fact in our head. We can debate what should have been managed better (PPE & testing) but we also know how damaging it is to have a policy of ‘all in this together’ when it emerges that it’s not being followed by those who argued in favour of it.