Complex sentence: For local government in the United Kingdom, England, Northern Ireland, Scotland and Wales each have their own system of administrative and geographic demarcation, consequently, there is "no common stratum of administrative unit encompassing the United Kingdom".
Split into simpler sentences: For local government in the United Kingdom, England, Northern Ireland, Scotland and Wales each has its own system of administrative and geographic demarcation. Consequently, there is "no common stratum of administrative unit encompassing the United Kingdom".