Ah, of course. Thanks for setting me straight. I have a sneaking feeling there may have been a certain Type 40 TARDIS involved as well, but I think we've pretty much cracked it.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'