Labour leader Jeremy Corbyn has admitted his party has "a lot of building to do" in Scotland, but "hung on" in England, after a mixed set of results in the UK's "Super Thursday" elections.
Labour has done better than pollsters expected in England, but was pushed into third place behind a resurgent Tory party in Scotland.
The SNP remained dominant in Holyrood, but lost its majority, meaning any plans for another independence referendum will likely be shelved, and Labour dominated in Wales despite losing its Rhondda "safe" seat to Plaid Cymru leader Leanne Wood.
Meanwhile, in London the results of the mayoral election are still to come in, but early indications put Labour's Sadiq Khan ahead of his Conservative rival Zac Goldsmith.
Here is a round-up of the results across the country:
The Scottish Parliament elections saw the SNP win its third Holyrood term, but the party failed to secure an overall majority.
Nicola Sturgeon termed the victory "historic", but her party lost the majority by two seats with 63 MSPs - six fewer than in 2011.
The First Minister said she was "desperate" for Scotland to become independent - but insisted that the decision over whether to hold a second referendum would lie with voters.
She has confirmed she will not seek to form a coalition with another party.
The Scottish electorate dealt a devastating blow to Labour, pushing the party down to third place in its former stronghold - and perhaps more humiliating, it is trailing seven seats behind the Tories.
It is the party's worst share of the vote in more than 100 years.
PM says Labour has 'lost touch' with people:
David Cameron congratulated leader Ruth Davidson and admitted his party's gains were "stunning".
If someone had come to my office and said 'Prime Minister, pretty soon the Conservatives are going to be the second biggest party in Scotland, I would have told them to go away, lie down, stop taking whatever they were taking and come back and tell me what they really thought, but that its what has happened.
Davidson won Edinburgh Central from the SNP, prompting bookies to slash the he odds on her being the next UK Conservative leader from 50/1 to 33/1.
Jeremy Corbyn admitted the party has "a lot of building to do" in Scotland, while Kezia Dugdale has vowed to continue as Scottish Labour leader despite what she called a "heartbreaking" result for the party.
SNP seats - two shy of a majority
Conservative seats - making it Scotland's second biggest party
Labour seats - a drop of 13 since 2011
Labour suffered losses in the English council elections, but the results were not as bad as many had expected and are likely to buy time for its embattled leader.
The party lost one council and more than 20 seats.
Reacting to the results, Mr Corbyn said the party had "hung on" and "grown support" in England.
Despite making the best of Labour's losses, members of Mr Corbyn's own party continued to criticise their leader.
Batley and Spen MP Jo Cox told ITV News "at this stage of the electoral cycle we should be winning far more seats".
Bermondsey and Old Southwark MP Neil Coyle - who nominated Mr Corbyn for the leadership - said Labour was "moving away" from the possibility of being in power come 2020.
Lost control of Dudley council in the West Midlands
Held on to major cities including Birmingham, Newcastle-upon-Tyne and Sunderland, as well as key southern outposts like Exeter, Southampton, Crawley and Slough
Kept two safe seats in parliamentary by-elections
The Conservatives lost overall control of Worcester but secured an absolute majority in Peterborough.
Labour dominated in Wales, but was rocked by the loss of its Rhondda "safe" seat to Plaid Cymru leader Leanne Wood.
Leighton Andrews, AM for the former coal mining valley in Wales between 2003 and 2016, lost by a majority of over 3,000.
Boosted by the proportional representation system, Ukip made the biggest gains. The party won its first seats in the Welsh Assembly - which up until 2013 it had wanted to abolish.
Nigel Farage's party gained seven seats in the Senedd, with former Conservative MPs Neil Hamilton and Mark Reckless among the winning candidates.
At 9pm on Friday 45 of the 108 seats n the Stormont Assembly elections were filled.
The Democratic Unionists had won 21, Sinn Fein 13, the Ulster Unionists four, Alliance three, SDLP two with People Before Profit Alliance and the Traditional Unionist Voice (TUV) landing one seat each.
Arlene Foster, the Democratic Unionist leader, expressed confidence she will be returned as Northern Ireland's first minister.
"I am confident that I will be the first minister of Northern Ireland," she said, after topping the poll in Fermanagh and South Tyrone.
However, the final outcome in Northern Ireland's elections is not expected until Saturday afternoon.
London Mayoral elections
Labour's Sadiq Khan won the mandate for London mayor on Saturday morning, beating Conservative candidate Zac Goldsmith and breaking the Conservatives' eight-year hold on City Hall.
Mr Corbyn hailed Mr Khan's victory, tweeting: "Congratulations @SadiqKhan. Can't wait to work with you to create a London that is fair for all! #YesWeKhan."
Mr Goldsmith's sister, Jemima Goldsmith, also tweeted her congratulations to the Labour candidate, and in a separate tweet criticised her brother's campaign, claiming it "did not reflect who I know him to be".