Labour has overtaken Reform UK in a major Westminster opinion poll for the first time in 16 months, capping Andy Burnham's first week as Prime Minister with his party's strongest showing since the early days of the current government.

A More in Common survey published on Sunday put Labour on 28%, up four points in a week and four points clear of Nigel Farage's Reform UK, which slipped two points to 24%. Kemi Badenoch's Conservatives were unchanged on 22%, the Liberal Democrats rose one point to 12%, the Greens fell three points to 8%, and the SNP polled 2% across the UK. The poll of 2,061 voters was carried out between 24 and 27 July.

The result marks the first time Labour has led Reform in a survey by the firm since March 2025, and ends a 16-month run at the top of the polls for Mr Farage's party. It is also the first poll from a major firm to place Labour ahead of Reform since April 2025, when YouGov gave Labour a one-point lead.

For Labour MPs, who moved to replace Sir Keir Starmer as leader earlier this summer amid a collapse in the party's standing, the figures offer early reassurance that the gamble on Mr Burnham may be paying off. In January, a More in Common poll had put Reform on 31% with Labour trailing on just 19%.

Luke Tryl, UK director at More in Common, said momentum was "clearly" with the Prime Minister but cautioned against reading too much into a single survey.

"It's only been a week since he entered office, but it's clear that momentum is on the Prime Minister's side," he said. "After a jam-packed week of high-profile policy announcements and media appearances, the Labour Party has surged in our weekly poll.

"With all the caveats that it's just one poll, Labour now leads for the first time since March of last year, and hold their highest vote share since the early months of this government in 2024. And with both Reform and the Green Party dropping to their lowest vote share in months, it seems that this early focus on the cost of living has appealed to voters that Labour has lost across left and right."

He added: "It's too early to see if this lead in the polls will be sustainable as Burnham makes his first moves and gets further into the practicalities of governing, but for the first time in a while, it seems that the government's electoral fortunes could be lifting."

Mr Burnham, who became Prime Minister on Monday, used his opening week to announce a series of measures aimed at providing "breathing space" on the cost of living. He said he would cut VAT on electricity bills from 5% to 0% for six months from October, a move he said would save the average household around £45, and confirmed the return of a £2 cap on bus fares in England, excluding London, from January. On Thursday, he pledged a 20% cut in business rates for pubs, clubs and music venues from next April, saying "pubs need to know the cavalry is coming".

The former Greater Manchester mayor also opened "No 10 North", an outpost of the Prime Minister's office in Manchester where he intends to work at least one day a week as part of a wider drive to move decision-making away from Westminster. He has described the bureau, which is expected to house around 300 civil servants, as "the nerve centre for a rewired Britain", though opposition politicians have dismissed it as a gimmick.

The poll comes as Reform endures one of its most difficult periods since the 2024 general election. The Parliamentary Standards Commissioner opened an investigation into whether Mr Farage should have declared a £5 million payment from crypto billionaire Christopher Harborne in his register of interests. Mr Farage has described the money, which he received before the last election, as a "gift" to fund his personal security and insists he has broken no rules, saying "no one cares" about the inquiry.

That investigation was paused after Mr Farage resigned as MP for Clacton earlier this month to contest the resulting by-election, which he framed as a "people versus the establishment" fight. The strategy appears to have backfired, however, after Labour, the Conservatives, the Liberal Democrats, the Greens and Restore Britain all declined to field candidates in what Mrs Badenoch called a "fake by-election". A record 34 candidates have been confirmed for the seat, with the novelty candidate Count Binface emerging as the focus of an anti-Farage tactical voting campaign. The by-election is due on 13 August.

An estimate from the seat projection tool Electoral Calculus suggested that, were the More in Common result repeated at a general election, Labour would be the largest party but around 25 seats short of an outright majority.

Not all polling points in the same direction. A YouGov survey released on Friday gave Reform a two-point lead over Labour, on 23% to 21%, with the Conservatives on 20%, underlining the uncertainty that remains despite Labour's improved standing.

Mr Burnham also faces early questions over party unity. On the same day the poll was published, he signalled that the government must "get really serious" about bringing down the welfare bill — a notable shift for a politician who, at Glastonbury in June 2025, urged MPs to vote against the whole of Sir Keir's welfare reform package. That earlier revolt, involving more than 100 Labour MPs, forced a government U-turn.

Whether the "Burnham bounce" proves durable is likely to become clearer over the coming weeks, with the Clacton by-election result, the outstanding standards ruling on Mr Farage, and the weekly polling tracker are all set to test the new Prime Minister's early momentum.