General principle of law or general legal principle refers to a principle that is recognized in all kinds of legal relations, regardless of the legal system to which it belongs.
It can also be a principle that is widely recognized by people whose legal order has attained a certain level of sophistication.
The United Nations Charter sets out the fundamental principles of modern public international law, notably: Promotion of human rights; The strict limitation on the right to use force against other states; The strict prohibition on the acquisition of territory by force.
In international relation, estoppel is a principle whereby a state is not able to say or act. against what it said or did before.
The theory of estoppel was originated in the past from. the English law system, which was later incorporated into international law.