At first these domains were free to register, but at some moment in time Icann asked Afilias to reserve these domains. Afilias then locked all that were still available and reclaimed some more in the Sunrise challenge.
Some weird things still happened, for example I got Schweiz.info (Switzerland) as Afilias made a spelling mistake: Schweitz.info is still locked.
Unitedkingdom is locked under the Icann rule, England.info was freely available as it is not an official country name: England is part of the country United Kingdom.