I think England is "on deck" for Qatar WC if they aren't 75% finished by 2016. FiFA does not want repeat of Brazil. I'll try to find article.
This is a possibility, but it's not certain.
What skelly is referring to is the way that FIFA have said before that there are only a couple of countries in the world which they consider to have both the stadiums and the infrastructure to handle being asked to host a WC at only a couple of months' notice, and therefore FIFA consider it likely (but not certain) that England would be asked to host if any country had to pull out. The rules about not giving a WC to the same continent twice in a row would just be ignored in this case because simply put there are not enough countries capable of doing this at no notice, and I'd suggest all of the ones in question are in Europe anyway.