I would only imagine that at this level of politics, our pm has bigger things to occupy their time.
Whoever manages his time/diary and others who manage him I would expect to research and know the rules.
That might work, @Summerwhereareyou, if he hadn't kept turning up on TV telling us what the rules were, or listening to other people telling us what the rules were. Was he not even listening to himself?
And then there's the fact that they simply must have discussed these things in cabinet; and that he was writing to little girls commending them for giving up their birthday parties because it was against the rules.
And even if he couldn't remember the rules he was instrumental in approving and telling us about, maybe he could have applied his mind to the reasoning behind the rules, i.e. to stop the spread of infection. He could have reflected on the fact that they had rather a lot of infections going around no. 10. If it was after he had covid, he could have reflected on that and how he got infected.
Or, if absolutely none of that crossed his mind, he could have thought about the basic rule every politician should apply to every action - i.e. if this was plastered across the front pages of the papers, how comfortable would I feel about it?
Johnson's got a degree, ffs, he shouldn't have to have a nanny to tell him what his own rules are.