Boris Johnson certainly wants the position and the prestige, but based on the evidence over the years, he is far happier as a performer than actually doing anything. He is often said to be uninterested in detail, so he will leave that to his underlings.

So I think we need to be rather more concerned with where Priti Patel , Liz Truss, Raab and one or two others end up, rather than Boris as PM as such.