Devolution is giving government powers to a less important government body. It is sometimes called Home Rule.
In the United Kingdom devolution has happened in Wales, Scotland and Northern Ireland. Each of these three countries now has an elected legislature which can pass some laws and a government to administer those laws and propose new ones.
These bodies are called
- The National Assembly for Wales, and the Welsh Assembly Government;
- The Northern Ireland Assembly, and the Northern Ireland Executive; and
- The Scottish Parliament, and the Scottish Government 
There is no devolution to Cornwall yet.
Devolved assemblies depend on the parent body. The British government could change its mind and abolish the devolved assemblies. This happened in 1972 to the government and parliament of Northern Ireland. It had been set up in 1920, with the parliament of Southern Ireland.
- legally called the Scottish Executive but in 2007 the new Scottish National Party government decided to use the new name