Reform UK made the first declared gain of election night shortly after midnight, taking the Chorley East ward from Labour as votes were counted across England and senior Labour figures conceded the party faced a difficult and potentially damaging set of results.

Polls closed at 10pm on Thursday after voters chose councillors across more than 100 English local authorities and cast ballots in elections to the Scottish Parliament and Welsh Senedd. English council results are expected through the night, but counting in Scotland and Wales will not begin until 9am on Friday, with the final Scottish outcome likely later in the day.

Because there is no overnight counting in Scotland and Wales, the English results are expected to shape the breakfast headlines and provide the first clear indication of how the main parties are performing.

The early Reform gain added to a tense mood in Labour less than two years after the party took power at Westminster. Deputy Prime Minister David Lammy said Labour had heard a “tough message on the doorstep” from voters frustrated by the cost of living and wanting the government to move faster. Asked whether Sir Keir Starmer should remain prime minister regardless of the result, Lammy did not answer directly.

Deputy Labour leader Lucy Powell also acknowledged that the elections would be “tough”, though she said Labour had run positive local campaigns and remained focused on delivering in government. Starmer’s first public comment after polls closed was a message on X thanking Labour members and volunteers for campaigning.

Forty-six of the 136 English councils voting are due to declare overnight, accounting for more than 1,200 seats, around a quarter of the total. Labour is defending more than 500 of those seats, or 43 per cent of the overnight contests, making the early hours a significant test of the party’s support. Analysts will also use the first declarations to estimate a National Equivalent Vote, a projection of how the parties would fare if the country were voting in a nationwide election.

Sky News election analyst Michael Thrasher said that if Labour were down about 200 seats by breakfast, the result would be bad but somewhat better than feared. If losses move towards 350 or more, he said, speculation over the future of Downing Street would intensify.

All seats are also being contested in 32 London boroughs, with 10 expected to declare overnight. Of the English councils counting through the night, 34 are electing only a proportion of councillors and 12 the whole authority, limiting the scope for some changes in control. Of the eight metropolitan boroughs declaring overnight, only Newcastle upon Tyne is electing the full council.

Other parties struck a more optimistic tone as polling stations closed. Reform UK’s Zia Yusuf said he was “confident” the party would do “extremely well” and suggested the results would herald “a new era of politics”. Liberal Democrat deputy leader Daisy Cooper said her party was “raring to go” and accused Labour of promising change and failing to deliver. Conservative chair Kevin Hollinrake said the night would probably be difficult for the Tories, but insisted they would continue to rebuild.

Green Party leader Zack Polanski predicted a record result in England and Wales. Plaid Cymru said there was a clear appetite for change in Wales. SNP leader John Swinney said he was waiting to see whether his party had secured a “historic and unprecedented” fifth term in office.

At the Basildon count in Essex, Sky News reported speculation that Reform could win all 14 seats being contested. Such an outcome would be politically significant in a council currently run by Labour as a minority administration. Reform currently has only one councillor in Basildon, elected in a by-election last year, but party figures and officials at the count were also reporting turnout levels closer to a general election than a normal local contest. Final Basildon results were expected at about 3am.

In Tameside, Greater Manchester, early piles of ballot papers suggested Labour and Reform were running close in the wards visible to reporters at the count. The borough overlaps with the area of the recent Gorton and Denton by-election, where the Greens took a parliamentary seat from Labour, but early signs there suggested the Greens were not matching that performance in the local races.

The unease inside Labour extended beyond the count centres. Privately, party figures were forecasting bleak results and warning of the political consequences if losses deepen. Greater Manchester mayor Andy Burnham, widely seen as a potential future leadership contender, withdrew from a speech he had been due to give in Manchester on Friday morning and was replaced by a member of staff, according to organisers. Sky News also reported that one Labour MP said they felt “sick” at the scale of the threat facing the party.

In Wales, where counting begins on Friday morning, Labour faces what could be its most serious challenge in more than a century. The party has led Welsh government for 27 years, and no non-Labour administration has ever run the Senedd, but polls have suggested that run could end. Welsh Labour figures privately told Sky News they were bracing for losses and feared First Minister Eluned Morgan could struggle to win a seat in Ceredigion Penfro.

Plaid Cymru and Reform UK both believe they can emerge as the largest party in Cardiff Bay, while the Conservatives face the possibility of a near wipe-out and the Liberal Democrats are not expected to make major gains. The Greens are also polling strongly enough to believe they could win their first Member of the Senedd, and possibly more than one.

The Welsh election is being held under a new system, with the Senedd expanding from 60 to 96 seats. The new parliament will be elected proportionately across 16 constituencies, each returning six members after being formed by merging two Westminster seats. A party would need 49 seats for an overall majority, a threshold widely seen as difficult to reach, making coalition-building or other cross-party arrangements likely.

In Scotland, 129 Holyrood seats are at stake, with 73 constituency contests decided by first past the post and 56 more allocated through regional lists. The SNP remains the party to beat after nearly two decades in power and is seeking a fifth term, although it enters the election after a turbulent period that included the departures of Nicola Sturgeon and Humza Yousaf and the continuing shadow of Operation Branchform.

Scottish Labour leader Anas Sarwar has tried to frame the election as a verdict on 20 years of SNP rule rather than an endorsement of Starmer’s government in Westminster, while Reform UK’s Scottish leader, Lord Malcolm Offord, has said his party can challenge for a leading role. Forecasts suggest the Scottish Conservatives could lose second place, while the Scottish Greens are aiming for gains and their first constituency win, and the Liberal Democrats could become important in post-election negotiations if no party commands a majority.

During the campaign, Scottish voters highlighted the cost of living, pressure on the NHS, drug deaths, ferries and prison overcrowding among their main concerns, underlining the demands facing whichever party or coalition eventually forms the next government in Edinburgh.

The breadth of parties expecting gains across different parts of Britain has reinforced expectations of a fragmented result. Sky News political editor Beth Rigby said the elections could come to be seen as the night two-party politics finally broke, with the electoral map turning into “a rainbow of colours” if the early trends are borne out.