The Lord President is appointed by a declaration of the sovereign in Council. To date all holders of the post have been men. In the twentieth century the Lord President has been both a departmental and a 'non-departmental' minister. As a departmental minister he has remained responsible for the Privy Council Office, and for presenting business to the sovereign and council at the formal meetings of the Privy Council, but these departmental duties have declined with the administrative responsibilities of the office, until by the early twentieth century the Lord President was free enough of heavy departmental responsibilities to be regarded primarily as a 'non-departmental' minister. Before the Second World War he was often a peer, sometimes leader of the House of Lords.
Subsequently his departmental responsibilities increased, principally in the field of scientific policy, where he had a dual responsibility. First, he became the minister responsible for the work of the research councils, a function derived from his constitutional position as president of the Privy Council committees to which these bodies were theoretically responsible, though in practice they were formal bodies which seldom met.
Secondly, and largely as a result of this first function, he became the minister responsible for general civil scientific policy and for co-ordinating work upon scientific questions which did not fall within the departmental responsibility of one or other of his colleagues. This sphere of his duties was marked by the appointment of the Lord President as chairman of the new Scientific Advisory Committee of the Cabinet in 1940, and by Sir John Anderson, as Lord President, being made personally responsible in 1941 for the development of research into the problems of nuclear fission. Though this latter responsibility was later separated from the office, by 1945 the Lord President was recognised as the minister with the main responsibility for civil scientific policy. From 1947 the Lord President was assisted by an Advisory Council on Scientific Policy, replacing the Scientific Advisory Committee of the Cabinet.
In January 1954 the Lord President took over from the Ministry of Supply responsibility for atomic energy, becoming chairman of the Cabinet Committee on Atomic Energy. On 1 August 1954 most of his atomic energy functions passed to the new United Kingdom Atomic Energy Authority, but the Lord President retained considerable jurisdiction in this field, possessing powers of supervision and intervention over the authority, appointing its members and being fully responsible to Parliament for its activities. In April 1957 these powers passed to the Prime Minister.
In November 1959 most of the remaining functions in respect of civil scientific policy, including the responsibility for the various research organisations, passed to the newly created post of Minister for Science, and in April 1964 certain residuary scientific functions passed to the Secretary of State for Education and Science.
In other respects the Lord President has acted as a 'non-departmental' minister, duties being assigned to the individual rather than the office, as determined by the Prime Minister, and varying according to the person appointed, the structure of government at the time, and the availability and suitability of other similar ministers.
During the 1940s the Lord President emerged as a powerful senior minister, usually one of the Prime Minister's leading colleagues, and responsible for much ministerial co-ordinatory work as chairman of various Cabinet committees. This was signified by the chairmanship of the Lord President's Committee, which during the war had a pre-eminent position on the home front. Prime Ministers came to look to the Lord President to assist them in the general conduct of Cabinet and Cabinet committee business and in the exercise of responsibilities for co-ordinating domestic policy. The extent to which this happened varied according to circumstances and personalities, but from Anderson's appointment in 1940 the Lord President acted under the Prime Minister as the chief co-ordinating minister for domestic policy, though the spheres assigned to him were not always the same. For example, Anderson as Lord President was entrusted with a special responsibility for the home front, and later for reconstruction problems. This latter function passed to a new Minister for Reconstruction in 1943, but returned to the Lord President in May 1945 when Lord Woolton combined the two offices.
Herbert Morrison, as Lord President in the post-war Labour government was responsible for economic co-ordination and economic planning until these functions passed to a new Minister for Economic Affairs in September 1947. He was also responsible for co-ordinating all government information services and general broadcasting policy, and the Central Office of Information was subject to his general supervision. These responsibilities passed to the Lord Privy Seal in March 1951, save those for co-ordination of overseas information which passed to the Foreign Secretary. Under the Festival of Britain (Appointment of Ministers) Order 1950 he was designated the appropriate minister for purposes of the Festival of Britain until replaced by the Minister of Works in March 1951.
When Lord Woolton returned to the Office of Lord President in 1951, his chief responsibility was to co-ordinate the work of the Ministries of Food and Agriculture, with a general duty of keeping an oversight of home affairs. With the successive reduction of his responsibilities in the scientific field the specific duties of the Lord President had been greatly reduced by the 1960s, and Lord Hailsham, who held the office from 1960 to 1964, not only combined the office with that of Minister for Science but undertook various additional ad hoc functions. He was responsible for the co-ordination of the development of sporting and recreational facilities and for advising the Cabinet on the means of reviving industrial activity in the north-east of England, and in December 1963 took over from the Treasury responsibility for university matters and for the University Grants Committee.
The small personal staff which Lords President had to assist them in their extra-departmental duties came to be known as the Office of the Lord President of the Council, to distinguish it from the Privy Council Office. From 1947 it included the scientific secretariat set up in the Cabinet Office in 1946, and transferred to the Lord President to assist him in connection with his scientific responsibilities, which also provided secretarial services for the Advisory Council on Scientific Policy and its sub-committees.
Also in 1947 an Economic Information Section of the office was constituted under a chief economic information officer, who was responsible for co-ordination of the information work of departments in so far as it had a bearing on the general economic situation. Responsibility for this section passed to the new Minister for Economic Affairs in September 1947.
From 1954 there was a separate Atomic Energy Office, responsible at first to the Lord President and later to the Prime Minister, to assist them in the discharge of their atomic energy functions. Both this and the Office of the Lord President were replaced in 1959 by the Office of the Minister for Science.