“International law is the body of rules which are legally binding on States in their intercourse with each other. These rules are primarily those which govern the relation of states, but states are not the only subjects of international law. International organizations and, to some extent, also individuals may be subjects of rights conferred and duties imposed by international law.”[1] “International Law” is the body of rules flowing from formal enactment or from custom pertaining to the relations between political states and regarded as binding on those states. It is some sort of substantive code of conduct governing relations between different “peoples”[2]. International Law consists of the rules and principles of general application dealing with the conduct of States and of international organizations in their international relations with one another and with private individuals, minority groups and transnational companies[3]. Whatever the connections international law has with other systems of law, it is clearly distinguished by the fact that it is not the product of any national legal system, but of the states that make up our world. In the past, international law was referred to as the Law of Nations[4] Customary international law describes common practices acknowledged as law by States. The development of customary international law is an unending progression, making it suppler than law enclosed in treaties. The task of identifying or describing customary international law, involves consideration of the following elements[5]:
  • the degree of consistency and uniformity of the practice;
  • the generality and duration of the practice;
  • the interests of specially affected States; and
  • The degree to which the States who adopt the practice do so from recognition that the practice is required by, or consistent with prevailing international law.
Principles of international law Most states have written constitutions that lay down the fundamental principles regulating social intercourse. Principles are the pinnacle of the legal system and are intended to serve as basic guidelines for the life of the world community. Besides imposing general obligations, they also set out the policy lines and basic goals of State agencies. The principles therefore represent the fundamental set of standards on which states are not divided and which allow a modicum of relatively smooth international relations. They make up the apex of the whole body of international legislation. They constitute overriding legal standards that may be regarded as the constitutional principles of the international community[6].International law is created and is deemed to be legally binding by authoritative national and international decision makers because they understand that generally agreed upon rules and principles of action serve the indispensible function of providing a basis for the orderly management of international relations[7]. International law “must be continuously developed by revision in content, expansion of scope, and improvement of the means of securing compliance so that it is kept in accord with the changing needs of the international community”. Since the present age is witnessing accelerating and meteoric changes on so many fronts, international law must also develop much faster that it has done in the past. If at any time, the lag between the law and changes taking place in the international fields widens too much, the resultant will be inevitable catastrophe. Indeed the future of mankind rests on the capability of International law to develop and adapt itself to the changing times and circumstances[8]. Elements of Customary Law Custom is an international habit of actions that has received full length attestation. Usage represents twilight stage of customs. Thus, custom begins where usage ends. In nutshell, custom is such a usage as has force of law[9]. Customary law has been evolved from the live out of the States. The actions of the states in the international arena give rise to obligatory law. The statue of International court of Justice describes customary law as a “general practice accepted by law”. As the International court stated in the Continental Shelf Case[10]: “It is of course axiomatic that the material of customary international law is to be looked for primarily in the actual practice and opinion juris of the states.”[11]  Article 38 of the Statue of International Court of Justice states that the court should apply ‘international custom, as evidence of a general practice accepted as law’. The statue, therefore, contains two requirements for the existence of international custom, namely, first there should be a sufficiently uniform practice, and secondly the belief that such practice is obligatory[12].
  1. State Practice
Any activity of the state can amount to state practice for the purpose of identifying the content of a legal rule; it is merely that different types of activity carry different weight[13]. Both physical and verbal acts of States constitute practice that contributes to the creation of customary international law. Physical acts include, for example, battlefield behavior, the use of certain weapons and the treatment provided to different categories of persons. Verbal acts include military manuals, national legislation, national case-law, instructions to armed and security forces, military communiqués during war, diplomatic protests, opinions of official legal advisers, comments by governments on draft treaties, executive decisions and regulations, pleadings before international tribunals, statements in international organizations and at international conferences and government positions taken with respect to resolutions of international organizations[14].
  • Consistency of practice
One of the most important factors in the formation of customary law is that the state practice must be reasonably consistent[15]. Customary international law results from the uniform and consistent conduct of states, undertaken with the conscious conviction on the part of states that they are acting in confirmation with law, or that they were required so to act by law[16].
  • Generality of practice
The practice must be significant to number of states. As the Anglo-Norwegian Fisheries Case [17]and North Sea Continental Shelf Case [18]illustrate, not all states need participate before a general practice can become law. In the Asylum Case[19], the court recognized that Art. 38 of the statue of the ICJ encompassed local custom as well as general custom in much the same way as it encompasses bilateral and multilateral treaties. Local customary law may exist where a practice has developed between two or more states, both or all of whom recognize the practice as binding[20]
  • Opinio Juris
It is not enough for the formation of customary law that there is general, uniform and consistent state practice. In order that this practice constitutes law, states must recognize it as binding upon them as law[21]. Opinio juris relates to the need for the practice to be carried out as of right. The particular form in which the practice and this legal conviction needs to be expressed may well differ depending on whether the rule involved contains a prohibition, an obligation or merely a right to behave in a certain manner. Opinio juris plays an important role, however, in certain situations where the practice is ambiguous, in order to decide whether or not that practice counts towards the formation of custom.[22] Opinio Juris is an essential element in the formation of customary law.
[1] Dr. S.K.Kapoor, International Law and Human Rights, 18th edn 2011, Central Law Agency [2] Public International law, University of Ottawa, Faculty of Law, Available at [3] Introduction to International Law, By Robert Beckman and Dagmar Butte available at [4] International law, Cambridge University Press, Handbook of International Law, Anthony Aust, available at [5] International law, State Library of New South Wales, available at [6] Antonio Cassese, international law, 1st edn, Oxford university press. [7] Dr. S.K.Kapoor, International Law and Human Rights, 18th edn 2011, Central Law Agency [8] Ibid [9] Gurdip Singh, International law, 2nd edn, Macmillan Publishers India Ltd [10] North Sea Continental Shelf (F.R.G. v. Den.; F.R.G. v. Neth.), 1969 I.C.J. 3 (Feb. 20) [11] Customary IHL, available at [12] Gurdip Singh, International law, 2nd edn, Macmillan Publishers India Ltd. [13] Martin Dixon, Textbook on International Law, Sixth edn, Oxford university press. [14] Customary IHL, available at [15] Martin Dixon, Textbook on International Law, Sixth edn, Oxford university press. [16] Olufemi Elais, The nature of the subjective element in customary international law, available at [17] 28 Brit. Y.B. Int’l L. 114 (1951), the judgment of ICJ Anglo-Norwegian Fisheries Case will rank among the boldest and most important judgments pronounced by any international tribunal. It lays down the rules of law which diverge fundamentally from those accepted by the majority of states at the codification conference on Territorial waters held at the Hague in 1930, available at Hein online [18] (F.R.G. v. Den.; F.R.G. v. Neth.), 1969 I.C.J. 3 (Feb. 20) [19] (Columbia v Peru), [1950] ICJ Rep 266 [20] Martin Dixon, Textbook on International Law, Sixth edn, Oxford university press. [21] Ibid [22] Customary IHL, available at
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