Update, 24 May 2017:
This is particularly informative and illuminating:
"The ninth variation was given the name 'Nimrod' after the biblical reference to Noah's great-grandson of the same name who was a gifted hunter. It pays tribute to Elgar's great friend Augustus J Jaeger (whose surname in German translates to 'Hunter') who managed to keep Sir Edward's hopes up while he was still trying to make his mark on the world of music. Elgar attempted to capture Jaeger's nobility in the slowness of the piece and (allegedly) tried to make a musical reproduction of a a conversation they once had late at night concerning the slow movements of Beethoven's slow pieces. Indeed, the first few bars closely resemble the very start of the second movement of Beethoven's Eighth Piano Sonata (also called Pathetique). Having said that, the piece also quotes from Mendelssohn at one point as well.
Perhaps it's due to the fact that the piece is always played at the Cenotaph on Rememberance Sundays that this piece of music captures - maybe more than even his celebrated Pomp and Circumstance - the essence of Britishness in a few pithy musical phrases. Jaeger's personal nobility aside, its slowness and languid fluidity seems to speak of stoical endurance, making do, fighting to the last bullet and of a small 'c' variery of conservatism that the sceptred isle will probably never shake off as long as we exist.
As for the music, I've loved this one variation above all the others since I was a child. Like everyone else I probably know it best from a muted brass band playing it on some Sunday every November, but the orchestral version offers so much more. The music appears to climb endlessly, like some kind of Escher staircase (or Shepard tone), playing with cadence, crescendo, tension and release in the most masterful of ways".
Many thanks to the author for his learned insight.