Labour has suffered losses across the country after Thursday's elections.
The party has seen a historic defeat in the Welsh Parliament and has lost both councils and councillors across many areas of England.
In Scotland the SNP remain the largest party at Holyrood but fall short of a majority.
Reform UK has performed strongly, taking control of 14 councils in England, coming second in the Welsh Parliament and tied for second in the Scottish Parliament.
The Green Party has also seen some victories, gaining five councils, two mayors and hundreds of councillors.
Check what happened where you live using our interactive tool and your postcode.
BBC analysis suggests a five-way split in how people across Great Britain might have voted had the whole country gone to the polls on Thursday.
Neither Labour nor the Conservatives would have had more than 20% of the vote according to the estimates. Reform UK would still have been out in front, but on a lower share than it had last year. The projection of the Green vote shows it at 18%.
Plaid Cymru won 43 seats in the Senedd but finished short of a majority. Reform came in second place with 34 seats.
Welsh Labour suffered a historic defeat, losing a national election in Wales for the first time in over 100 years. It saw significant losses including its leader and First Minister Eluned Morgan. It finished third overall, ahead of the Conservatives, with the Greens taking two seats and the Liberal Democrats one.
This year, the Senedd has expanded from 60 to 96 seats and the boundaries have changed too.
The old constituencies and regions have been replaced with 16 new constituencies, each electing six members using a system of proportional representation.
Labour held half of the seats after the last election in 2021.
At Holyrood the SNP are by far the largest party in the Parliament but do not have enough seats for a majority.
Party leader John Swinney retained his Perthshire North seat but there were some constituency losses to the Liberal Democrats, Greens and Labour.
All other parties are a long way behind.
Reform UK picked up its first seats in the Scottish Parliament, ending the counting tied for second place with Labour. The Scottish Green Party were third followed by the Conservatives and Liberal Democrats.
Labour has lost control of more than 30 councils. They include losing Birmingham City Council, which had been Labour-run for 14 years, to no overall control where five parties have at least a dozen councillors each.
It has lost councils like Sandwell in the West Midlands and Barnsley to Reform UK as well as losing some to the Conservatives and the Greens.
Reform UK gained more than a dozen councils including Sunderland, Thurrock, Suffolk, Essex, Havering and Newcastle-under-Lyme and more than 1,400 councillors across the country.
The Green Party of England and Wales has taken Norwich, Hackney, Waltham Forest and Hastings councils and has gained hundreds of councillors across England.
The Liberal Democrats also gained many councillors and took control of the new councils in West Surrey and East Surrey. They also won Portsmouth and Stockport but lost control of Hull.
The Conservatives have lost more than 550 seats and control of seven councils but regained control of Westminster in London.
There were more than 5,000 councillors up for election across 136 councils in England on Thursday.
Labour were defending the most seats with more than 2,500, the Conservatives over 1,300, the Lib Dems just under 700 and the Greens just under 150.
Most of the seats were last contested in 2022, at a time when Reform UK stood in very few areas. That means it stood to gain the most of all the parties.
The map below shows how it has picked up seats across England at a district level.
Use the tabs to see the other parties.
Before the election London was a Labour stronghold but the map in the city now looks more multicoloured.
The Greens have won both the mayoral and council races in Hackney and Lewisham and have taken control in Waltham Forest.
The Conservatives have retained control of all the councils they held and also gained Westminster.
Reform UK has gained Havering, Aspire gained Tower Hamlets and the Liberal Democrats have kept control of three London councils.
Interactive tool produced by Wesley Stephenson, Jess Carr, Allison Shultes, Steven Connor, Scott Jarvis and Chris Kay.
Reporting and visualisations by Aidan McNamee, Daniel Wainwright, Christine Jeavans, Becky Dale, Libby Rogers and Rob England.
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