Votes are being counted in elections across Scotland, Wales and parts of England that could prove a decisive moment in Sir Keir Starmer’s premiership.
Labour is expected to suffer heavy losses throughout the country as the party languishes in the polls and faces challenges from Reform UK to the right and an insurgent Green Party to the left.
Polling guru Lord Robert Hayward has suggested Labour could lose some 1,850 councillors in England.
The party is set to lose the national vote in Wales for the first time in more than a century, while in Scotland the SNP appears likely to remain the largest party.
As polls closed, Deputy Prime Minister David Lammy said the elections had been “tough”.
He said: “I don’t want to sugarcoat it, the message from the doorstep is this is a tough election cycle.
“This is a mid-term set of elections with people concerned about the cost of living and wanting to see the Government go faster with quicker pace.”
Mr Lammy added that while Labour had run a “positive campaign”, the party’s “message of delivery” had been “drowned out by the politics of grievance”.
A national drubbing is also likely to reignite speculation about Sir Keir’s leadership of the party and the country.
Before polls closed, The Times reported that Energy Secretary and former Labour leader Ed Miliband had privately urged the Prime Minister to set out a timetable for his departure after the elections.
Other Cabinet ministers are said to be considering leadership tilts, including Health Secretary Wes Streeting and former deputy prime minister Angela Rayner.
Allies of Ms Rayner are confident she would be able to gain the support of the 81 MPs required to launch a challenge – a number which Mr Streeting is also said to have met, though neither is said to want to be the first to move.
Greater Manchester Mayor Andy Burnham, who is said to have a plan to return to Westminster within weeks, has dropped out of giving a speech on Friday morning.
Mr Burnham had been expected to address the second annual Festival of Childhood in Manchester on the morning after the elections, but on Thursday evening organisers said he had been replaced by Caroline Simpson, group chief executive of the Greater Manchester Combined Authority.
But Mr Lammy insisted Sir Keir would remain in office, pointing to poor local election results seen by other prime ministers who went on to win re-election.
He said: “I remember, after our huge victory in 1997, a very bad set of election results for Tony Blair in 1999.
“David Cameron lost successive local elections when he was in office, but went on to win the 2015 election.
“So it’s not unusual to be given a message by the electorate at mid-term elections.”
Mr Lammy also warned against playing “pass the parcel” as the Tories did “with leader after leader”, telling the BBC: “There are questions that we have to answer, but.. there is no circumstances in which the answer to the questions that the British people are raising is to change the leader yet again.”
Meanwhile, Nigel Farage’s Reform UK is set to make significant gains, building on last year’s local elections that saw the party pick up almost 700 councillors and take control of 10 authorities.
Pointing to the fragmentation of the traditional two-party duopoly, Reform’s Zia Yusuf told the Press Association: “We are used to, in our lifetimes, Labour or the Conservative Party winning majorities in general elections with north of 40% of the vote.
“And I think now, they are going to struggle to get 40% between them, and I don’t think they’re coming back. I think the Greens are going to eat a lot into Labour.
“I think Reform are going to eat a lot into Labour.
“Keep an eye on those Labour heartlands, you know, in the Red Wall. Those areas, I think, are going to move decisively turquoise. I think there’s going to be a turquoise wave throughout that area.”
The Greens are also expected to do well, with new leader Zack Polanski predicting “record-breaking local elections” for the party, while Sir Ed Davey’s Liberal Democrats are eyeing an eighth successive year of local gains.
Predicting gains in London, Newcastle, Sussex and Wales, Mr Polanski said: “The news from the doorstep is that we will be taking seats from not just Labour but the Tories and Lib Dems too, from all across the country.”
Sir Ed said his party had knocked on three million doors during the campaign, twice its total last year, adding: “In former Conservative heartlands and old Labour strongholds alike, we are standing up for decency and real change.”
But it could be another bad night for the Conservatives despite an improvement in party leader Kemi Badenoch’s approval rating, with the party expected to lose further ground to Reform.
Tory chairman Kevin Hollinrake said the party had run “an energetic and positive campaign”, but acknowledged the elections would be “difficult” coming two years after “a historic general election defeat”.
Almost 25,000 candidates were fighting to be elected to more than 5,000 seats on 136 councils across England, where six local mayoral contests also took place.
In Scotland, all 129 seats were up for election at Holyrood while voters in Wales were choosing 96 members of the Senedd.
