Voters in two of the UK’s devolved nations, Scotland and Wales, are preparing to go to the polls on Thursday 6 May.
Scots will cast their ballots to elect MSPs to Holyrood, whereas those in Wales will vote to elect MSs to the Senedd.
These national parliaments, and the Northern Ireland Assembly, have the power to oversee devolved issues including health, education, housing, justice and the environment.
But how did devolution come about, and how does it work?
Here is everything you need to know.
What is devolution?
Devolution is centred on how parliaments and governments make their decisions.
Scotland, Wales and Northern Ireland, along with England, were governed solely from Westminster, London, for many years.
The current form of devolution in the UK stems back to the late 1990s.
In 1997, Tony Blair’s Labour government was elected under the promise of creating devolved institutions.
The same year, in referendums, voters chose to create a Scottish Parliament and a National Assembly for Wales (now called the Senedd), in the hope that the administrations would be more representative of the people within the two nations.
Devolution for Northern Ireland came one year later, and was a key element of the Belfast (Good Friday) Agreement.
How does devolution work in each country?
Although it is the same concept, devolution works slightly differently within each of the nations.
There are now four different legislatures and executives, each with a differing range of powers.
In Scotland, 129 elected MSPs sit at Holyrood in Edinburgh.
Before devolution, the country already had its own legal and education system. After the referendum, more responsibility was given in areas including agriculture, environment, health, housing, justice, transport, taxes and some welfare powers.
The devolved powers in Scotland have been extended twice - once in 2012 and once in 2014 following the “No” vote in the independence referendum.
However, the SNP, which has formed the government at Holyrood since 2007, is seeking a fourth term in office and an overall majority to gain a strong mandate for another Scottish independence referendum.
The party has also called for further devolution since the UK left the EU following the Brexit vote.
Meanwhile, the Senedd Cymru (Welsh Parliament) is based in Cardiff Bay and is made up of 60 MSs.
Until May 2020, it was known as the National Assembly of Wales.
The government has many of the same responsibilities as Holywood, including agriculture, education, environment, health, housing and transport while also having power over the Welsh language.
How is the set up different in Northern Ireland?
And in Belfast, the Northern Ireland Assembly sits at Stormont, with 90 elected MLAs.
Devolution in the nation is different to the powers afforded to Scotland and Wales.
Instead of a range of responsibilities, the administration’s powers are divided into three categories.
The first is transferred powers, controlled by the Northern Ireland Assembly and including agriculture, education, environment, health, justice, transport and culture.
Then there are reserved powers, which remain in Westminster but could be transferred in future if the Northern Ireland Executive decides, such as prisons and civil defence.
Finally, there are excepted powers which cannot be moved to Stormont without special laws being made in Westminster, including elections and national defence.
The nationalist and unionist communities in the country also share power, with the First Minister and Deputy First Minister representing each of the two largest parties and co-leading the government through a mandatory coalition.
After Northern Ireland’s government was dissolved in January 2017, following the breakdown of relations between the DUP and Sinn Féin, three years later the two parties agreed to work together again alongside three smaller parties.
What does devolution mean for the UK Government?
Along with the establishment of the three institutions, the UK Government also developed decentralisation in England.
That means the transfer of powers, budgets and responsibilities to local and regional mayors over the past 20 years.
Mayors now have power in areas such as transport and housing.
The first Mayoral position created was the mayor of London, alongside the London Assembly, following a referendum in 1998.
Then, mayors in other parts of the country were created after referendums in 2002 and 2012.
They have different powers depending on the area.
In Greater Manchester, the mayor oversees social care, children’s services and housing, while in London the mayor can set bus and Tube fares and decide targets for the number of affordable homes.
But the government in Westminster is still responsible for policy in England as well as overall policy for a number of issues, including defence, national security, foreign policy, immigration, citizenship and tax.
However, in Scotland, the government is able to raise and lower income taxes.
The four administrations communicate with each other to ensure devolution is successful.