The British statute book contains countless references to “the Secretary of State.” At first glance, this hardly seems surprising. However, those four words mask a surprising level of complexity.
Should you visit the Downing Street website in order to identify the Secretary of State, you will immediately find yourself in a quandary—there are no fewer than eighteen individuals with the title ‘Secretary of State.’ Which one of them is the Secretary of State?
The answer is: they all are. This is due to a strange bit of constitutional metaphysics. In theory, there is only one Secretary of State. However, that single office is held by multiple people (e.g., the Secretary of State for the Home Department, the Secretary of State for Foreign and Commonwealth Affairs, the Secretary of State for Defense, etc.) But in the eyes of the law, there is still only one Secretary of State, and the various occupants are technically interchangeable. In other words, the Secretary of State for Foreign and Commonwealth Affairs could decide to march over to the Home Office and take command there.
This curious arrangements arose in the reign of Henry VIII. In April 1540, Thomas Cromwell (of Wolf Hall fame) resigned as the King’s Secretary after being raised to the peerage as Earl of Essex. Instead of being succeeded by a single person, he was replaced by Thomas Wriothesley and Ralph Slater acting jointly. While Cromwell may have suggested this arrangement because he wanted to make sure that no one else could use the Secretaryship as a springboard to power like he had, it also appealed to Henry VIII since it prevented one official from becoming too powerful. Although this probably started out as a temporary arrangement, the Secretaryship continued to be held by two individuals for the rest of Henry’s reign and into the reigns of Edward VI and Mary I. Elizabeth I and James I resumed the practice of appointing a single Secretary, but the practice of dividing the office became the norm after 1614.
As the seventeenth century progressed, it became customary to draw de facto distinctions between the two Secretaries of State. Initially, they were differentiated by their diplomatic responsibilities. One Secretary was responsible for relations with Spain, Portugal, Flanders, Italy, and Ireland, while his colleague was responsible for France, Holland, the Baltic states, Germany, and Turkey. This arrangement was formalized in 1662 by the creation of the ‘Northern Department’ and the ‘Southern Department. Both men shared responsibility for domestic affairs, however, and this arrangement persisted until 1782 when Charles James Fox was given responsibility for foreign affairs while Lord Shelburne oversaw domestic affairs. The eighteenth century saw the appointment of additional Secretaries, though it wasn’t until the twentieth century that their numbers really grew.
The modern practice is to create a new ‘subdivision’ of the Secretaryship whenever a new government department is created. One advantage to this arrangement is that it makes it incredibly easy for the Prime Minister to alter the structure the government. He can advise the Queen to create new Secretarial titles and government departments by Order in Council whenever he sees fit, and Parliament need not be consulted.
Although the idea of one office with eighteen occupants is more than a little bizarre, there haven’t been any calls to rationalize it. It may be confusing, but it doesn’t really do any harm. Absent any clarion calls for change, I suspect this little constitutional oddity may well stick around for another 400 years.
 In formal parlance, they are referred to as “Her Majesty’s Principal Secretary of State for…”
 A good overview of the development of the office of Secretary of State can be found in A. J. C. Simcock, “One and Many—The Office of Secretary of State,” Public Administration, vol. 70 (Winter 1992), 535-553.
 In practice, however, this does not actually happen.
 At that time, the office of Secretary was basically a clerical position, and Cromwell may have felt that it was incompatible with his new dignity as an earl Simcock, 539.
 The dual nature of their appointment is confirmed by the tenor of their warrant of appointment, which can be found in State Papers Published Under the Authority of His Majesty’s Commission, Volume 1, Henry the Eighth Parts I and II (London: John Murray, 1831), 623-624.
 Simcock, 539-540.
 The title of ‘Secretary of State’ replaces that of ‘King’s Secretary’ after 1600. Simcock, 540.
 Simcock, 541.
 Rodney Brazier, Ministers of the Crown (Oxford: Clarendon Press, 1997), 9.
 Brazier, 10.