Devolution in the UK created a national Parliament in Scotland, a national Assembly in Wales and a national Assembly in Northern Ireland. This process transferred, and continues to transfer, varying levels of power from the UK Parliament to the UK's nations - but kept authority over the devolved institutions in the UK Parliament itself.
Scotland, Wales and Northern Ireland all held successful referendums on devolution in the late 1990s. This led to the establishment of separate Parliaments or Assemblies and the democratic election of officials.
Devolved and reserved powers
Devolved powers are decisions that Parliament controlled in the past, but are now taken by the separate bodies, e.g., the Scottish Parliament. This could include matters like education or health.
Reserved powers including, amongst others, UK defence and foriegn policy remain with Parliament in Westminster.
In each case, the legislation establishing the separate bodies determined which powers were devolved and which were reserved. Ultimately Parliament can still legislate on devolved matter but generally doesn't do so.
Transfer of powers
The Scottish Parliament and the National Assembly for Wales took responsibility for their devolved powers on 1 July 1999, the Northern Ireland Assembly followed on 2 December 1999.
The Northern Ireland Assembly was suspended at midnight on 14 October 2002. Power was restored to the Northern Ireland Assembly on 8 May 2007.
Since the original transfer of powers, new legislation has also seen other powers devolved to Scotlands, Wales and Northern Ireland.