The Ministry of Health inherited the powers and duties in the field of public health and medical services of the Local Government Board and the National Health Insurance Commissions except the latter's functions in respect of medical research, which passed to a newly incorporated Medical Research Council under the supervision of a committee of the Privy Council. The Medical Research Council did, however, continue to work closely with the ministry. At its inception the ministry also received the powers formerly held by the Privy Council under the Midwives Acts of 1902 and 1918.
In 1919 five health divisions were formed and the health functions of the ministry divided between them. For some time the Food and Drugs Branch was a separate division, but later formed part of one of the other divisions.
Further transfers of powers led to the consolidation of the health functions of the government in the ministry and the removal to other departments of specialised powers not directly related to general health policies. From the Home Office were transferred infant and child life protection functions under the Children Act 1908 in October 1919, powers under the Anatomy and the Lunacy and Mental Deficiency Acts, including ministerial responsibility for the Board of Control, in May 1920, and health provisions of the Factory and Workshops Act 1901 in England and Wales in May 1921. Subsequently, other functions were transferred from the Home Office relating to wartime services.
In December 1919 duties relating to the medical inspection and treatment of children and young persons and in 1925 administration of grants for the training of midwives and health visitors were similarly transferred. The Board of Education remained responsible for the drafting of regulations, payment of grants and approval of schemes for the school medical service, subject to the general supervision of the Minister of Health. In 1919 the medical officer of the Ministry of Health was appointed medical officer of the board also.
In 1920 powers to regulate company water undertakings were taken over from the Board of Trade, the minister already having responsibility for local authority water undertakings. In 1922 powers of pest control in ports and vessels were transferred from the Ministry of Agriculture and Fisheries and were later exempted from the transfer of functions relating to pest control from the Ministries of Health and Food to the Ministry of Agriculture and Fisheries in 1947.
The ministry's concern with food control was reduced in November 1943 when power to regulate the labelling and composition of food was transferred to the Ministry of Food. In 1948 certain administrative duties under the Food and Drugs Acts 1936 to 1944 were similarly transferred, but were restored in 1955, when responsibility for welfare foods passed to the ministry from the Ministry of Agriculture, Fisheries and Food (MAFF), although the latter acted as procurement agent.
The ministry took over functions relating to medical supplies from the Ministry of Supply and the Board of Trade in 1947, and responsibility for the provision of appliances, vehicles and medical and surgical treatment from the Ministry of Pensions in 1953. In 1947 most of the staff and functions of the Board of Control were transferred to the ministry, and when the board was abolished in 1960, following the Mental Health Act 1959, some of its remaining duties passed to the department.
Under the 1947 Polish Resettlement Act, the ministry was responsible for the provision of hospitals for Polish nationals, although the Ministry of Pensions acted for the ministry on an agency basis until 1953. In 1955 responsibility for welfare foods passed to the Ministry from MAFF although the latter acted as a procurement agent.
In 1948 the Home Office took over central responsibility for children deprived of a normal home life, who were in local authority care.
The National Health Service Act 1946 provided for the bringing together of the disjointed system of independent health and medical services under overall control of the Minister of Health, and the local responsibility for services provided by Regional Hospital Boards and Executive Councils being taken over Local health Authorities. The object was to provide a comprehensive service to everybody, free of charge, the cost being met through National Insurance contributions, taxes and rates. Apart from some of the administrative functions of the Board of Control concerned with mental health, which were transferred to the Minister of Health on 1 July 1947, all other provisions of the Act came into force on 5 July 1948.
The emergence of the ministry as a specialist department of health after 1951 led to the formation of more specialised divisions and, in particular, divisions responsible for supervision of the National Health Service. These included a Hospital and Specialist Services Division (which later developed into three divisions) an Executive Councils Division, a Health Services Superannuation Division, a Health Services Remuneration and Staffing Division (later forming two divisions) and a Hospital Supplies Division. There was also a Local Authorities Division dealing with local health and welfare services, an International Health, Food and Nutrition Division and a Civil Defence Division.
On the creation of the Department of Health and Social Security in 1968 these divisions were transferred to it without reorganisation. Local and regional health bodies and regional offices were also concerned in the working of the National Health Service.