Subsidiarity of Estoppel as a Means of Law Protection Against Unfair Behaviour in Relation to Civil Law Institutions

Estoppel received its formalization through the consolidation of legal regulation in the form of separate norms quite recently. Before that, its manifestation could be found in a few judicial practice. Today estoppel is becoming more widespread, which inevitably raises numerous questions about its use. The work carried out a comprehensive study to substantiate the subsidiary nature of estoppel as a remedy in relation to civil law institutions. Earlier in science, attempts were made to identify the signs and essence of estoppel, to give it a definition, and also considered special cases of estoppel using the example of judicial practice and new legal regulation. However, until now, no conclusions have been formulated about the validity of its subsidiary nature, the possibility of using estoppel as a means of protection in principle in all areas of civil law. It seems most correct to define estoppel as a prohibition of contradictory and inconsistent behavior that undermines reasonable and reasonable trust, arising from the general principle of good faith and being its particular manifestation. The stated legal approach makes it possible to apply estoppel to situations not directly regulated by legislation.