Davenport is a career police officer, doing his time first as a 'bobby on the beat' and later as a detective in Scotland Yard. The exact details of how he ended up as the head of the Watch are shrouded in folklore, but he likes to tell people that he lost a bet and this was the losing wager.
The thing that marks Davenport as so very different from the average Watch member is that he has absolutely no magical power or connection of any sort. In fact, some people have said that his magical power is just that; a total and utter lack of magic.
That isn't to say that Davenport is ignorant of the magical world - far from it! He is a savvy player in a city drenched in supernatural in-fighting.