In reply to AndyE9:
Do you mean 0°12'00" (as in 0 degrees, 12 minutes, and for the sake of argument 0 seconds)?
And by short distances, you mean any distance you're ever likely to walk a bearing over?
Pedantry aside, it raises a number of interesting questions:
How long before it's ever worth making the correction again on the UK mainland? (I.e. gets anywhere close to being worth adjusting on a compass, maybe half a degree if you're very dextrous, and with good eyesight)
How many of us will ever use it again on home turf given advances in technology and/or time it takes to be significant again?
Will all those old mnemonics go out the window in future? (I.e. will the direction, and hence the correction reverse?)
How will it be different in different places, e.g. Ireland, Scottish Islands, and maybe the far north of Scotland?
I'm off to do a little googling...