Northern Ireland, Scotland and Wales each has its own government or executive, led by a First Minister, and a devolved, unicameral legislature. England, the largest country of the United Kingdom, has no devolved executive or legislature and is administered and legislated for directly by the UK government and parliament on all issues. This situation has given rise to the so-called West Lothian question which concerns the fact that MPs from Northern Ireland, Scotland and Wales can vote, sometimes decisively, on matters affecting England that are handled by devolved legislatures for their own constituencies.

The Scottish Government and Parliament have wide ranging powers over any matter that has not been specifically 'reserved' to the UK parliament, including education, healthcare, Scots law and local government. Following its victory at the 2007 elections, the pro-independence Scottish National Party (SNP) formed a minority government with its leader, Alex Salmond, becoming First Minister of Scotland. The pro-union parties responded to the electoral success of the SNP by creating a Commission on Scottish Devolution which reported in 2009, recommending that additional powers should be devolved, including control of half the income tax raised in Scotland.

The Welsh Assembly Government and the National Assembly for Wales have more limited powers than those devolved to Scotland, although following the passing of the Government of Wales Act 2006, the Assembly can now legislate in some areas through Assembly Measures passed within clearly defined areas based upon Legislative Competence Orders which can be granted on a case-by-case basis. The current Welsh Assembly Government was formed several weeks after the 2007 elections, following a brief period of minority administration, when Plaid Cymru joined Labour in a coalition government under the leadership of First Minister Rhodri Morgan until December 2009, after which Carwyn Jones became First Minister.

The Northern Ireland Executive and Assembly have powers closer to those already devolved to Scotland. The Northern Ireland Executive is led by a diarchy, currently First Minister Peter Robinson (Democratic Unionist Party) and deputy First Minister Martin McGuinness (Sinn Féin).