All registered electors who were aged 18 or over on polling day were entitled to vote in the local elections. A person who had two homes could register to vote at both addresses as long as they were not in the same electoral area, and could vote in the local elections for the two different local councils. Individuals had to be registered to vote by midnight twelve working days before polling day. Anyone qualifying as an anonymous elector had until midnight on 25 April 2017 to register.
Seats held prior to the election
In total, 4,851 council seats were up for election in 88 councils; additionally six new mayors were directly elected. Approximately 10,000 people were candidates for election. All 32 councils in Scotland and all 22 councils in Wales were up for election; an additional 34 councils in England were up for election. Of the 35 English councils up for election, 27 were county councils, seven were unitary authorities, and one was the Doncaster Metropolitan Borough Council. According to a BBC News estimate, taking into account boundary changes, the major political parties were effectively defending the following notional results in council seats on election day:
There were also 687 independent councillors and 4 Mebyon Kernow councillors. The remaining 217 seats were held by residents' associations and minor parties. A by-election for the parliamentary constituency of Manchester Gorton was due to be held on the same day as the local election, but the by-election was cancelled after the general election was called for the following month.
Results
Overall results - Great Britain
As elections were not held throughout the country, the BBC calculated a Projected National Vote Share, which aims to assess what the council results indicate the UK-wide vote would be "if the results were repeated at a general election". The BBC's preliminary Projected National Vote Share was 38% for the Conservatives, 27% for Labour, 18% for the Liberal Democrats and 5% for UKIP, with others on around 12%. This is the highest vote share for the Conservatives in local elections since 2008, when they faced Labour a decade into government and suffering from the financial crisis. The Liberal Democrats have performed better than at any election since 2010, whilst Labour has not performed so badly since 2010. UKIP lost 145 of their 146 seats. Prominent former UKIP members talked of the party being finished and that it should disband.
Results by nation
England
Note that unlike in Scotland and Wales, where all local authorities were up for election, the England results are for only 34 councils out of 353, and should not be taken as reflective of the whole of England.
Wales
For comparative purposes, the table above shows changes since 2012 including Anglesey's council, which was last elected in 2013.
All 27 county councils for areas with a two-tier structure of local governance had all of their seats up for election. These were first-past-the-post elections in a mixture of single-member and multi-member electoral divisions. These were the last elections to Dorset and Northamptonshire county councils.
Unitary authorities
Seven single-tier unitary authorities held elections, with all of their seats up for election. These were first-past-the-post elections in a mixture of single-member and multi-member electoral divisions or wards.
Six elections were held for directly elected regional mayors. These newly established positions lead combined authorities set up by groups of local councils, as part of devolution deals giving the combined authorities additional powers and funding. Other planned mayoralties have been postponed or cancelled. The election of the Sheffield City Region Combined Authority mayor was postponed in January 2017 and, following legal action, did not occur until the 2018 local elections. The North East Combined Authority deal was scrapped as several councils in the region voted down the proposal, however the smaller North of Tyne combined authority was approved by the councils and by parliament for the 2019 local elections. The other devolution deals that were scrapped were for the Norfolk and Suffolk, Greater Lincolnshire and the Solent. There were concerns at the low turnout recorded.
