Historically the power to make a guardianship order was derived from the ancient concept of parens patriae where the guardian looked after and cared for those who could not care for themselves. Later guardianship, like so much else in modern health legislation, became bound up with the Poor Law, at least for the less well off. It was developed by the 1913 Mental Deficiency Act and later by the 1959 Mental Health Act where it was refined and extended, though hardly ever used. Under the 1983 Act, the major provisions of which can be found in Sections 7–10, guardianship has been retained although, under this Act, there are restricted powers of the guardian. These restrictions were introduced in order to encourage greater use: this is not a paradox, for it was thought that the guardian's earlier powers were excessive and represented too much of an imposition on the patient. However, as will be shown later, this in my view is an oversimplification; in spite of changes, guardianship is no more popular than hitherto.

One can see how guardianship and the Poor Law were linked. Guardianship means the supervision by one person, the appointed guardian, over the patient. The Poor Law guardians were responsible for those unable to care for themselves and, as mentally disordered people often required supervised care, the duties of the guardian were assumed.