In the United Kingdom, devolved matters are the areas of public policy where the Parliament of the United Kingdom has devolved its legislative power to the national legislatures of Scotland, Wales and Northern Ireland, while reserved matters and excepted matters are the areas where the UK Parliament retains exclusive power to legislate.
Devolution in the United Kingdom is regarded as the decentralisation of power from the UK Government, with powers devolved to the Scottish Parliament and Scottish Government, the Northern Ireland Assembly and Northern Ireland Executive and the Welsh Parliament and Welsh Government, in all areas except those which are reserved or excepted. Amongst the four countries of the United Kingdom, Scotland has the most extensive devolved powers controlled by the Scottish Parliament, with the Scottish Government being described as the "most powerful devolved government in the world".