Part of the answers to those questions lies in the decision to not build up our testing capability rapidly. We had echoes of it last night. The question was asked why are we still letting flights arrive from places with higher levels of infection than we currently have without testing or isolating the passengers? We were told the science said it would have little or no affect on the spread. Which is nonsense, I am afraid. True, adding x cases to a situation where you already have 100x has little impact, but as the advertisement has it 'every little helps'. Any one of those incoming passengers could start a new centre of infection if they go to an area that was relatively free from the infection.

More likely, the fact that a single jumbo could easily contain 400 passengers means that a policy of testing incoming flights would completely swamp our current testing facility. We tested 19,116 on 9/4, which is something like the equivalent of 40 jumbo jets.   So even testing one or two of these would divert a significant proportion from the front line. If you have the capability to test hundreds of thousands, you will have the capacity test incoming flights, but (in my opinion) the reason we don't test flights is that we don't have the capacity.