When a conversation is so loud that the sound of it extends into the street, you can hardly expect it to be private.
" When a conversation is so loud that the sound of it extends into the street, you can hardly expect it to be private."
Note that the article has NOT stated what the threshold will be at which sound can be intelligibly monitored (which may be quite different from that at which a noise offense will be considered to be committed).
Personally, I would not underestimate the inclination of the British government to monitor its subjects, and to take all possible steps towards enhancement of said capacity.