D.M. Pick gives me a more accurate distillation of his `uk' explanation :-)
diff --git a/Tools/world/world b/Tools/world/world
index 581d585..6b9132b 100755
--- a/Tools/world/world
+++ b/Tools/world/world
@@ -281,10 +281,13 @@
"int": "international",
# This isn't in the same class as those above, but is included here
# because `uk' is the common practice country code for the United Kingdom.
- # AFAICT, the official `gb' code is routinely ignored! David Pick
- # <D.M.Pick@qmw.ac.uk> tells me that `uk' was long in use before ISO3166,
- # but in reverse order (e.g. uk.ac.qmc) and this was just carried over
- # into the New World of the Internet.
+ # AFAICT, the official `gb' code is routinely ignored!
+ #
+ # <D.M.Pick@qmw.ac.uk> tells me that `uk' was long in use before ISO3166
+ # was adopted for top-level DNS zone names (although in the reverse order
+ # like uk.ac.qmw) and was carried forward (with the reversal) to avoid a
+ # large-scale renaming process as the UK switched from their old `Coloured
+ # Book' protocols over X.25 to Internet protocols over IP.
#
# See <url:http://www.ripe.net/docs/ripe-159.html#222123>
"uk": "United Kingdom (common practice)",