When I was much younger, out having lunch with my sister once, we were bothered a couple of times by a lunchtime imbiber who wanted to chat us up. he asked (the last time him came up to our table) what we did, as we 'seemed stuffy'. My imagination kicked in and I said ' I am a military policewoman and she's a psychiatric nurse'.
We werent, we were both civil servants, but it got rid of the botherer and gave us a good laugh. I think I remember correctly I used it about 2-3 times more.
Fascinating causes of death 1632

I always said "I am a Civil Servant" & if asked further I would say "I worked for the Treasury".