Legislation generally refers simply to "the secretary of state" without further elaboration. By virtue of the Interpretation Act 1978,[5] this phrase, when used in legislation, means "one of His Majesty’s Principal Secretaries of State".[6] Despite there only being one office of Secretary of State, in practice, more than one person will be appointed to carry out the office's functions, each within their own portfolio.[2][7] As there is only one office of Secretary of State, any secretary of state can act on another's behalf. Home secretary John Simon said in a debate in the House of Commons in 1936:
Of course, originally, there was only one Secretary of State, and, indeed, in one sense it may be said that even today there is only one office of Secretary of State, because anyone who is a Secretary of State may lawfully and constitutionally perform any act that can be done by any other Secretary of State. If I may for a moment call on my own personal experience, I happened to be Secretary of State for Home Affairs at the time when [Secretary of State for War] Lord Kitchener made his last fatal journey from this country, and just before he sailed from these shores I had a message from the War Office asking me whether I would sign his papers until he came back. I continued to give the formal signature which it is legitimate for any Secretary of State to put upon the papers of any other Secretary of State, and I did so until the news came of his death. Constitutionally, the office of Secretary of State is held by a number of persons who may be regarded as all one.[8]
Secretaries of state, like other government ministers, are appointed through the royal prerogative.[9]
Most secretaries of state are incorporated as a "corporation sole". This gives the minister a separate legal personality, allowing continuity in areas such as the ownership of property between office-holder changes.[7]
In 1782, the responsibilities of these offices were changed, so that one would be responsible for foreign affairs and one for domestic affairs, thus establishing the embryonic offices of foreign secretary and home secretary.[2][11] Over time, the number of secretaries of states grew, so that there were five in 1900 and 14 by 1996.[2] There are currently 16 secretaries of state.[3]
Health, education, work, business, energy, environment, transport and the regions
The secretaries of state that have been used for the matters of health, education, work, business, energy, environment, transport and the regions are shown in the graphic below. It shows how portfolios of responsibilities have been broadly passed down from one secretary of state position to the position(s) directly below it. However, it is impossible for such a graphic to be completely accurate; it cannot show smaller changes, or gains or losses of responsibilities within a position due to changes of responsibilities for the UK Government (for example, due to devolution or Brexit). It is not to scale. In the gaps, and before the first of these secretaries of state, relevant responsibilities were taken on by ministers not titled 'Secretary of State'.
^"Government ministers". Institute for Government. Retrieved 1 February 2021. What are the different types of minister? The most senior government ministers, except the prime minister, are secretaries of state.
^"Ministerial and other Salaries Act 1975, Schedule 1, Part V, Paragraph 2". legislation.gov.uk. Retrieved 1 February 2021. In the case of the following offices a salary may be paid to more than one holder of the office at the same time, subject to the limitations expressed below, that is to say— (a) Secretary of State, so long as not more than 21 salaries are paid at the same time in accordance with Part I above;
^ abSainty, J. C. (1973). "Introduction". Office-Holders in Modern Britain: Volume 2 - Officials of the Secretaries of State 1660-1782. British History Online. University of London. pp. 1–21. At the Restoration [in 1660] the practice of appointing two Secretaries of State, which was well established before the Civil War, was resumed. Apart from the modifications which were made necessary by the occasional existence of a third secretaryship, the organisation of the secretariat underwent no fundamental change from that time until the reforms of 1782 which resulted in the emergence of the Home and Foreign departments. ... English domestic affairs remained the responsibility of both Secretaries throughout the period. In the field of foreign affairs there was a division into a Northern and a Southern Department, each of which was the responsibility of one Secretary. The distinction between the two departments emerged only gradually. It was not until after 1689 that their names passed into general currency. Nevertheless the division of foreign business itself can, in its broad outlines, be detected in the early years of the reign of Charles II.
