MI6 is being rebuilt from the ground up in every possible sense, largely due to this situation. It is therefore vital that all agents and operatives have a thorough understanding of exactly what went down - and blew up. Classification has proven tricky, but any serving member who pays attention will be able to piece together a good 90% of what occurred, along with at least another 90% of improbable extras. "M", has, however, apparently plugged the power vacuum, for the time being - and closed down a lot of avenues of 'idle speculation'.
The shadow of this event will be incalculable, and colour all events here (on the wiki). Most personnel of that era refer simply to "SI" or "Ellie" (ELE - Extinction Level Event). If you don't understand the term, you don't belong in the conversation. With the seismic shift of Spectre, the paranoia levels within the organisation have reached their breaking point, and the tidal forces are driving and compelling a sea change.