The thing that I think hasn't been totally internalised is just how good the path the UK is on is. At the current run rate (430k average), we should have vaccinated 57% of the country, with a first jab, by the start of April - which is when we need to start doing second doses. https://twitter.com/HugoGye/status/1357629746662821894
If you want to hit all adults by the end of May, increasing the daily dose delivery by around 166,000 from the start of March does it. That's all!
In short, if ministers and officials are saying first doses to all adults by July, and Priority groups by May, the question should be "Why, what's going to go wrong?"
This would represent a big slowdown in vaccinations! https://twitter.com/SebastianEPayne/status/1357642146606645250
That also impacts this: The total time this should be relevant for is maybe two and a half months, and probably less. https://twitter.com/iainmartin1/status/1357614337477795841