A unitary state is a state governed as one single unit in which the central government is supreme and any administrative divisions(sub national units) exercise only powers that their central government chooses to delegate. The great majority of states in the world have a unitary system of government.
Important unitary states are United Kingdom, Ukraine, People’s Republic of China, Egypt, France, Singapore, Sri Lanka, Japan, Saudi Arabia etc.
How UK government is properly described as unitary form of government…..
Jeff Reiman who teaches at Grandview High School in Aurora, Colorado wrote:
"I understand why the government [in the UK] is properly described as unitary. But under my reading of the Good Friday Agreement, Parliament seems to have permanently ceded such powers to the newly-created legislature for Northern Ireland. (I believe similar provisions appear in Parliament's agreements establishing regional assemblies in Scotland and Wales.) The Good Friday Agreement also provides that the people of Northern Ireland can vote to secede from the U.K. -- establishing far greater regional sovereignty than exists under the U.S. Constitution. Doesn't this mean Parliament has now created a federal system of government?"
Well, I have read neither the Good Friday Agreement nor the Scotland Act, so I didn't have an answer beyond the textbook assertion that the system in the UK is unitary.
I started by looking at the Scottish Parliament web site. I learned there that the Scotland Act of 1998 describes two kinds of powers: devolved powers and reserved powers. The Scotland Act describes the powers reserved for Parliament in Westminster. The Scottish Parliament's web site says that devolved powers, "such as education, health and prisons" are now given to the Scottish Parliament.
A web site called AdviceGuide.org, ("the online Citizens' Advice Bureau service that provides independent advice on your