In message , John Salmon
writes

As a matter of interest, where did 'IG' come from? In my view, its
derivation is the least obvious of all the postcodes. I can work out
all the other slightly obscure ones e.g. SP=Salisbury Plain,
DG=Dumfries & Galloway etc., but the only suggestion I've ever heard
for IG is Ilford & Gants Hill, which seems unlikely.

I always understood it was linked to Ingatestone as being in the middle
(roughly) of the area.
--
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