Regarded historically, the law of prescription is merely a branch of the law of custom. A prescription was originally conceived as a personal custom, that is to say, a custom limited to a particular person and his ancestors or predecessors in title. It was distinguished from a local custom, which was limited to an individual place, not to an individual person. Local and personal customs were classed as the two species of particular customs, and as together opposed to the general customs of the realm. Coke distinguishes as follows between custom (i.e. local custom) and prescription.[[150]] “In the common law, a prescription which is personal is for the most part applied to persons, being made in the name of a certain person and of his ancestors, or those whose estate he hath; or in bodies politique or corporate and their predecessors.... And a custome, which is local, is alleged in no person, but layd within some mannor or other place.”

Since prescription and custom were thus regarded as two species of the same thing, we find, as might be expected, that they are originally governed by essentially similar rules of law. The requisites of a valid prescription were in essence the same as those of a valid custom. Both must be reasonable, both must be immemorial, both must be consistent with statute law, and so on. It was only by a process of gradual differentiation, and by the later recognition of other forms of prescription not known to the early law, that the difference between the creation of customary law and the creation of prescriptive rights has been brought clearly into view. In the case of custom, for example, the old rule as to time immemorial still subsists, but in the case of prescription it has been superseded by the statutory rules contained in that most unfortunate specimen of legislative skill, the Prescription Act. A prescriptive right to light, for instance, is now finally acquired by enjoyment for twenty years. Usage during this period is now an absolute title, instead of, as at common law, merely evidence of usage during time of memory.

SUMMARY.

Historical importance of customary law.

Reasons for the recognition of customary law.

Requisites of a valid custom:

1. Reasonableness. 2. Opinio necessitatis. 3. Consistency with statute law. 4. Immemorial antiquity (unless general).

History of this rule.

5. Consistency with the common law (unless immemorial).

Conventional customs.