The same 51% rule, all the way down. A constituency comes online; a majority of constituencies activates a region or nation; a majority of nations activates the United Kingdom. Drill in, switch on, watch it climb.
0.0%
United Kingdom · nations online
0 of 0 online · 0 needed for 51%
The United Kingdom stands activated — its nations have chosen.
A majority online. The compact is rewritten by those present.