For a long time in the science of labour law, domestic researchers have been engaged in scientific discussions about recognizing legal custom as a source of labour law.
Sources of law are usually considered in a formal and substantive sense. In a formal sense, the sources of law are forms of its external expression in the most general terms, in a substantive sense, causes and preconditions by which the right in question arose. Further, for scientific and practical purposes, sources of law are considered precisely in terms of the formal approach.
Traditionally, the legal custom is considered as "an established rule of conduct that has become obligatory as a result of frequent and uniform repetition in a certain area of activity" [1].
From the point of view of the theory of law, A.S. Konovalova distinguished four main concepts of customary law: autonomous, positivistic, natural law and sociological [2]. The autonomous concept (H. Hugo, C. Savigny, H. Puchta) is reduced to the study of customary law as a self-sufficient legal phenomenon within a particular people, the positivistic concept (V.A. Tumanov) is reduced to the recognition of customary law only if it is recognized by the state in one form or another, the natural law concept (Epicurus, Thomas Aquinas) focuses on the relationship between law and justice, the sociological concept of law (A.N. Filippov, E. Ehrlich, L. Duguit, G. Gurvich) considers customary law as a set of legal rules created independently of the prescriptions of the legislature.
However, there is no unified understanding of legal custom as a source of labor law so far.
Thus, A.S. Konovalova proposes, using an innovative integrative method, to combine all the listed concepts into one [2, З. 44], and V.V. Ershov and E.A. Ershova see the possibility of combining legalistic and sociological concepts [3]. A.V. Kryzhan sees the sanctioning of custom as a legal requirement for customary law [4].
At the same time, concerning the recognition of legal custom in labour law of the Russian Federation, there is a lively debate about the recognition of legal custom as a source of labour law in Russia in 1) the Constitution; 2) the Russian Labour Code and other laws governing labour and related relations; 3) judicial practice. It should be noted that legal custom as a source of law, in the absence of such an establishment in the Constitution, is fully recognized at the legislative level in the civil and housing legislation.