Devolution is а transfer of the legislative powers of the Westminster Parliament to the parliaments of the historical provinces once united with England into the United Kingdom, which are directly elected by the provincial population. That delegation is asymmetrical and revocable, but it does not affect the basic norms of the British unwritten constitution on parliamentary supremacy. Over the devolution the provinces do not acquire the primary competence, but the one that is given to them by the transfer of the legislative powers of the Westminster Parliament. A special law retaining the Westminster Parliament’s primary competence and sovereignty grants this competence. Regarding the scope of the devolved powers of the provinces and the organizational mechanism for their execution, there is a significant asymmetry. In all the provinces, there is a unique junction between devolved powers and their holders. Before the referendum on the independence in Scotland in September 2014, the increase of devolved powers was promised not only for all the historical provinces (Scotland, Wales, Northern Ireland), but for England as well, which represents a step towards the federalization of the UK. Devolution and several other institutions of the British constitution also, have a stamp “Made in Britain” which does not allow easy imitation and transfer to another countries and their constitutions.