I think it's worth stressing that in the UK the 24-hour clock is ubiquitous. Yes, we use the 12-hour clock almost exclusively in speech ('let's meet at half five', 'did you see the 10 o'clock news?') but most BE speakers are processing both the 12 and 24-hour clock all day long, and not just those in the listed example professions, or on public transport.
In an hour my computer and phone will both read 13:49; newspaper articles online will be published with the 24-hour time; the bus timetable says the next bus is at 15:20; the clock in the waiting room will say 18:24, etc. etc. A colleague might answer -- reading from their phone -- "fourteen forty-two" -- in response to a request for the time.
I think AE speakers underestimate how much the 24-hour clock is used in the UK, and BE speakers overestimate how widespread it is in the US. All of this is evident in this thread :)
#15 -- is that the World Service? I know the World Service uses 24-hour. I haven't listened closely for a long time, but I would expect the (not World Service) BBC to use 12-hour. So a programme might be advertised as 'starting at 10pm on Sunday'. And a newsreader would always begin with 'welcome to the six o'clock news'.