A long night of counting has revealed blows for Labour in Scotland and south of the border, after elections seen as the first nationwide verdict on Jeremy Corbyn's leadership of the party.
Here are the key highlights as the results from polling day roll in.
The typically speedy Labour-stronghold Sunderland was the first to declare all of its results, with Labour gaining an extra seat.
While Labour held on to two safe seats in Westminster by-elections and losses in English councils were lower than some predicted, frustrations with Jeremy Corbyn's leadership bubbled to the surface.
Labour lost control of Dudley council in the West Midlands, but held on to major cities including Birmingham, Newcastle-upon-Tyne and Sunderland, and bellwether authority Nuneaton.
Conservatives lost overall control of Worcester but secured an absolute majority in Peterborough.
Ukip gained seats in Thurrock, Tamworth and Bolton and looked set to secure its first representation on the Welsh Assembly.
There was better news for Labour in Liverpool, where Joe Anderson was re-elected as mayor with more than 50% of the vote. Local Leigh Labour MP Andy Burnham revealed he was considering running for mayor of Greater Manchester.
Labour suffered a major blow in its south Wales heartlands as Plaid Cymru leader Leanne Wood ousted Labour government minister Leighton Andrews.
Nicola Sturgeon declared the SNP has "made history" by winning a third term in government at Holyrood.
Scottish Conservative leader Ruth Davidson made clear she expected to head the main opposition party at Holyrood as Labour looked set to slump into third place in Scottish Parliament polls, losing more than nine points in its share of the vote.
Davidson secured a seat at Holyrood by winning Edinburgh Central from the SNP, while Scottish Labour leader Kezia Dugdale was left relying on the top-up system for a seat as she failed to take Edinburgh Eastern.
Labour lost Scottish Parliament seats Rutherglen, Greenock & Inverclyde, Cowdenbeath and Edinburgh Northern & Leith to the Scottish National Party and Eastwood to the Conservatives.
A mini-bounceback by Liberal Democrats north of the border saw leader Willie Rennie return to Holyrood by winning North East Fife, while the party also took Edinburgh Western from the SNP and held on to the Orkney and Shetland islands.
One of the biggest political prizes up for grabs, the London mayoralty, will not be decided until Friday evening, with Labour's Sadiq Khan looking to wrest control of City Hall back from the Tories and defeat his Conservative rival Zac Goldsmith.
Goldsmith has been criticised for his campaign tactics by senior Tory Andrew Boff. He said the campaign had "done real damage" and had "blown up" bridges the party had built with London's Muslim communities.
Counting will start on Friday morning with the first declarations expected at about 1pm and the final results expected late on Saturday.