For those who appreciate British humour...Sir Humphrey tries to explain the levels and roles in Govt thus......quoted verbatim...

Jim Hacker: "Humphrey, do you see it as part of your job to help Ministers make fools of themselves?"

Sir Humphrey: "Well, I never met one that needed any help! The traditional allocation of executive responsibilities has always been so determined as to liberate the ministerial incumbent from the administrative minutiae by devolving the managerial functions to those whose experience and qualifications have better formed them for the performance of such humble offices, thereby releasing their political overlords for the more onerous duties and profound deliberations which are the inevitable concomitant of their exalted position."

The PS is thus referred by title 'CMG' - call me god.
The minister has the title 'KCMG' - kindly call me god.
Then ultimately the Prime Minister title is 'GCMG' - god calls me god.

For more juice... <http://www.yes-minister.com/episodes.htm>