The fact that R in London doesn't seem to have been hugely different from the rest of England, and that the trajectory of deaths has followed a similar form (in fact dropping off more quickly than much of the UK I think) suggests that it's not been responsible for a large proportion of transmission there.The Government need to supply the scientific evidence (and when I say evidence I mean real evidence not a theoretical paper produced by some retired professor) that travelling on public transport carries a high risk of catching COVID because I'm getting sick of this constant "do not use public transport" message.
We need evidence that a high proportion of those who have caught COVID in London caught it on the tube. Otherwise its all guesswork.
Having said that, much as I wish we didn't have the anti-public transport theme at the moment, I don't think we're at the stage where we should abandon all precautions until someone can prove there is a danger. We know that people spread coronavirus, we know it's quite contagious, and putting people together in an air conditioned vehicle for extended periods of time is unlikely to be good.
But if London can tolerate the tube, the overall impact on R of letting somebody board a 158 through a locally opened door might be something we could live with.