> The political nightmare of convincing the non-British part of the world that "sorry, your day of the week is going to switch in the middle of the afternoon",

> The political nightmare of convincing the non-British part of the world that "sorry, your day of the week is going to switch in the middle of the afternoon", for example, hasn't even been mentioned yet. This is the main real objection. My solution for UIT (http://kybernetikos.github.io/UIT http://kybernetikos.github.io/UIT) was to have two different kinds of day, the international day, which switches at .0 UIT and goes nullday, unday, duoday, triday, quadday, pentday, hexday, heptday, octday and nonday, and the local day which switches at local solar midnight (modulo DST) and goes sunday, monday, tuesday, wednesday, thursday, friday, saturday. The clockface shows when they both change, so it's not too difficult in use. Point being, when someone says "Lets meet on IRC at .4:20 21st Nonday" it refers to a particular time in a year anywhere in the world unambiguously (the 219th day of the year, zero indexed). It's pretty inelegant, but the idea is you would use the local day names when talking to people in the same place as you, and the international days when arranging something with someone physically separated from you.