I'm sure the UK will be much safer after doing the traffic analysis on a billion emails for penis enlargers. Maybe they can use the get rich from home emails to fund the project. I am perfectly happy to help by forwarding the contents of my junk email folder.
The Home Office insists the data ... does
not include e-mails' content ...
They are effectively only keeping the headers. It still lets them do traffic analysis, of course. Beside, nothing will provoke the general populace into using crypto, it will have to be forced on them.