From the beginning of March 2018, Camden have taken it upon themselves to fine drivers who leave their engines running.
I am sceptical though, and wrote to the press about this: article attached.
From recent requests the past 3 months have not gone well: not one person has been prosecuted and yet EVERY day I walk past engines idling. Why is this? Because the campaign to fine is not working. They are not monitoring how many warnings have been given. Then we would know how effective it is.