Permanent Under-Secretary of State
A Permanent Under-Secretary of State also known more commonly as the Permanent Secretary is the most senior civil servant of a government ministry or department in the United Kingdom, charged with running the department on a day-to-day basis. Similar offices, often employing different terms, exist in many other Westminster-style systems and in some other governments.
Permanent secretaries (known by other names in some departments; see below) are the non-political civil service heads (and "accounting officers") or chief executives of government departments, who generally hold their position for a number of years (thus "permanent") at a ministry as distinct from the changing political secretaries of state to whom they report and provide advice. Examples of this office would be the Permanent Secretary to the Admiralty or Permanent Under Secretary of State for War.