It is called Devolution - Devolution is the statutory delegation of powers from the central government of a sovereign state to govern at a subnational level, such as a regional or local level. It is a form of administrative decentralization. Devolved territories have the power to make legislation relevant to the area, thus granting them a higher level of autonomy.

Devolution differs from federalism in that the devolved powers of the subnational authority may be temporary and are reversible, ultimately residing with the central government. Thus, the state remains de jure unitary. Legislation creating devolved parliaments or assemblies can be repealed or amended by central government in the same way as any statute. In federal systems, by contrast, sub-unit government is guaranteed in the constitution, so the powers of the sub-units cannot be withdrawn unilaterally by the central government (i.e. without the consent of the sub-units being granted through the process of constitutional amendment). The sub-units therefore have a lower degree of protection under devolution than under federalism.