Sir Keir Starmer is facing his first test at the ballot box as Prime Minister on May 1.
It’s a big day for Labour, with millions of people set to deliver their verdict on the party’s rocky return to Downing Street.
But it’s the Tories who are likely to be hit the hardest, polling suggests, while Reform UK is expected to make inroads across the country.
Here, The Telegraph takes a look at the seats to watch on Thursday night and throughout the day on Friday.
Runcorn and Helsby: Labour’s first by-election test
Result expected: Friday, 3am
The vote that threatens to cause the biggest headache for Sir Keir on May 1 is technically not a local election at all.
While councils across England go to the polls, No 10 will be keeping close tabs on the parliamentary by-election in Runcorn and Helsby, where Nigel Farage is hoping to snatch another seat in the Commons for Reform.
The vote was triggered by the resignation of Mike Amesbury, the former Labour MP who was jailed for punching a man in the street. He stepped down after his conviction, with his prison sentence suspended on appeal.
A mix of rural and industrial communities along the Mersey, in a quiet corner of Cheshire, Runcorn and Helsby is fertile ground for disaffected Labour voters to pivot to Reform.
The insurgent Right-wing party was already starting to creep up on Labour at last year’s general election. Amesbury won the constituency with a sizeable 22,358 votes, or 52.9 per cent of the total, with Reform placing second on 7,662, or 18.1 per cent.
What started as a drain on Labour’s lead has morphed into a full-blown threat to its majority, with Reform now widely tipped to swipe the seat from under Sir Keir’s nose.
A recent poll by More in Common suggested Labour would lose the constituency at a general election, with a 19.5 point two-way swing to Reform.
Politicians will tell you to ignore the polls. But local Labour members are clearly lacking confidence, with 53 per cent believing Reform will win, while just 23 per cent have faith in their own side.
It is the Prime Minister’s first by-election test since entering No 10, with voters finally able to have their say on a string of controversies including the freebies scandal, the inheritance tax raid and sweeping cuts to benefits.
All by-elections are unique, but Runcorn and Helsby has the potential to set the mood music for the months and years ahead.
Doncaster: The only Labour council up for grabs
Result expected: Friday, 5am
As the only Labour-held council up for election on May 1, a loss in Doncaster would be a disaster for the Prime Minister.
The party currently has a substantial majority, with just under 75 per cent of seats. It would appear to be in a strong position after the last election, with all three of the Westminster constituencies covering parts of the city won by Labour in July.
However, a mega-poll by Electoral Calculus carried out in March put the council on track to fall to Reform at the local elections.
If this comes to pass, it would be a huge upset. The local MPs who could find themselves under pressure include Ed Miliband, the Energy Secretary and former Labour leader, in Doncaster North.
Crucially, any major shift is unlikely to come from a minority demographic, with just 2.2 per cent of the local population identifying as Muslim, while 19.4 per cent are over 65, broadly similar to the national average. That means any swing could be an indicator for the wider electorate.
The local mayoral seat is also up for grabs, with Labour’s Ros Jones hoping for a fourth consecutive term. She beat her Conservative rival by 15 points in the first round of voting in 2021, while Reform’s Surjit Duhre took only 1.6 per cent.
Reform’s pick for 2025, Alexander Jones, is hoping to capitalise on Sir Keir’s rocky start to power with a stronger performance this time round.
But he’s had a turbulent campaign of his own, coming under fire for links to an account that praised the self-proclaimed misogynist Andrew Tate. If he can put the controversy behind him and win in Doncaster, it would be a major coup for Mr Farage.
Durham: A key Labour-Reform battleground
Result expected: Friday, 1pm
Labour is tantalisingly close to a big win in Durham, but its hopes of a breakthrough are likely to be dashed by Reform.
The party is just short of a majority on the county council, with 56 out of 126 seats as of last May. On a good night, it could wrestle control from the hodgepodge administration of Tories, Lib Dems and independents, bringing the authority back into Labour hands after its 100-year hold was broken in 2021.
The wind was in Labour’s sails at last year’s general election, with the party taking seven out of the eight parliamentary seats in the area.
However, hopes of a takeover are likely to be scuppered by a surge in support for Reform, which is expected to have one of its best performances of the night in Durham. According to the March poll, the insurgent party is set to take 70 of the 98 council seats on offer on May 1, or 71.4 per cent of the total.
Reform came second in five of Labour’s general election victories in the area last year, supplanting the Tories as the local opposition and laying the groundwork for a strong showing at the local elections.
Staffordshire: A Tory stronghold under threat
Result expected: Friday, 4pm
True-blue Staffordshire county council has been under Conservative control since 2009, with the party holding 92 per cent of seats as of last May.
To all intents and purposes, it’s a Tory stronghold. But with Kemi Badenoch’s party expecting an “extremely difficult” night on May 1, we could be in for another upset.
While the council has been in Conservative hands for more than 15 years, it was actually held by Labour between 1981 and 2001, proving it is by no means infallible.
Now, Reform is on the prowl. Having won just 421 votes last time around, equal to 0.3 per cent of the Tories’ haul, it is expected to benefit from a surge in support on May 1.
According to March’s mega-poll, Reform is set to become the largest party on the council without winning an outright majority, overtaking the Tories with 30 councillors.
That would be a dramatic loss for the Conservatives, and a huge embarrassment for Mrs Badenoch. One for Tory supporters to watch through their fingers.
Cambridgeshire and Peterborough and West of England: A test for the ‘youth vote’
Result expected: Friday, 3pm (Cambridgeshire and Peterborough) and 2am (West of England)
While Sir Keir faces a challenge from Reform on the Right, he is also battling to keep the Left on side after a string of controversial decisions that saw one of his former MPs accuse him of “Austerity 2.0”.
The mayoral elections in Cambridgeshire and Peterborough and the West of England could be seen as a test of his success, given their big student populations in Cambridge and Bristol.
These are bellwethers for the young, who tend to be Left-leaning and form a crucial part of Labour’s voter base. With widespread anger on university campuses over issues such as the war in Gaza and the transgender debate, students could use May 1 as an opportunity to send a message to the Prime Minister.
In the latest census, 13.7 per cent of Bristol’s population and 9.5 per cent of Cambridge’s were students, relative to 7.9 per cent for England as a whole.
A new YouGov poll suggests Labour will take a drubbing in Cambridgeshire and Peterborough. The Tories are expected to come out on top, followed by Reform.
Things are a bit more complicated in the West of England, where it’s looking to be a close race between Labour and the Greens.
The vote will be particularly sensitive for Labour following the arrest of its outgoing mayor, Dan Norris, on suspicion of rape and child sex offences.
The 65 year-old, who has previously worked as a teacher and an NSPCC-trained child protection officer, was immediately suspended by the Labour Party when the news broke in April.
Mr Norris, who is also a sitting MP, was already barred from standing for a second term as mayor because of a change in the Labour rules preventing him from holding both roles at once. Instead, Labour is fielding a new candidate, Helen Goodwin, who is a former local councillor.
The West of England mayoral winner is likely to be the first to be declared at around 2am, potentially providing an early indication of the way the wind is blowing.
Devon and Cornwall: Lib Dem tanks on Tory lawns
Result expected: Friday, 6pm (both)
It’s no secret that the Lib Dems are taking the fight to traditional Tory heartlands at the local elections, and the South West is a prime target.
The Tories currently dominate at local level in Devon and Cornwall, but things are changing fast.
Cornwall Council was won by the Conservatives in 2021, but slipped to no overall control with the Tories as the biggest party last year. The Conservatives currently have 41 out of the 87 seats to the Lib Dems’ 13.
In Devon, leadership has ping-ponged from the Tories to the Lib Dems over the past 50 years. The Conservatives’ hold there is more solid, with 38 out of 60 seats, compared to just nine for the Lib Dems.
However, these leads are a hangover from the Tories’ sweeping gains at the local elections in 2021, when Boris Johnson was riding high on the Covid “vaccine bounce”.
The Liberal Democrats made big progress in the South West at last year’s general election, snatching 21 constituencies from the Tories, while the Conservatives’ vote share in the region fell from 52.8 per cent in 2019 to 28.2 per cent in 2024.
It means there is ample potential for an upset on May 1, with the Lib Dems predicted to be the largest party on Cornwall Council in March’s mega-poll.
Greater Lincolnshire: Tory defector tipped to win for Reform
Result expected: Friday, 3.30am
When Dame Andrea Jenkyns defected to Reform after losing her Tory seat last year, she likened her former party to a sinking ship.
She’s now hoping to prove the point by beating the Conservatives to the Greater Lincolnshire mayoralty on May 1.
The area has long been blue, with the Tories holding 53 out of 70 seats on Lincolnshire county council. But this is a brand new mayoralty, and a golden opportunity for Reform.
According to the new YouGov poll, Dame Andrea is set to storm to victory with 40 per cent of the vote. It puts her 15 points ahead of her closest rival, the Tories’ Rob Waltham, while Labour trails in third.
It would be a huge win for Mr Farage as he attempts to cement Reform as a major electoral force capable of challenging Labour and the Tories in every corner of the country.
