I clearly understand that I can personally do nothing about someone wanting to blow me up. If I am on a train with a brown man with a backpack, I do not think it likely he is going to kill me. If it is neat, I think he is going to work. If it is enormous, I think he's probably visiting relatives. If there are wires hanging out of it I think, hey, he hates airpods too. He's just a brown man with a backpack.

I do, however, accept that some brown men with backpacks have blown up tube trains, that the direct causes of that are things I may not even know about, that the risk has not gone away at all, and that indeed at some points the risk may be severe. I can't know which.

But the security services can.

I can decide not to be paranoid about being watched, too.