The Green Party has moved into second place ahead of Labour in a new YouGov Westminster voting intention poll, in a significant shift in the party political landscape less than two years after Labour’s landslide general election victory.

The poll, conducted by YouGov for Sky News and The Times, puts Reform UK in first place on 23%, down one point on the previous survey. The Greens are second on 21%, up four points, while Labour has fallen to 16%, down two points, level with the Conservatives on 16%, also down two. The Liberal Democrats are unchanged on 14%.

Sky News said it was the first time the Greens had placed second in YouGov’s regular Westminster voting intention series, and the 21% score represents the party’s highest ever recorded by the pollster. For Labour, the figures mark a new low in recent YouGov polling while in government.

The survey was carried out across 1–2 March among 2,073 adults, with changes measured against YouGov’s previous poll. As with all single polls, the results are a snapshot of opinion at one moment and may be subject to normal polling variation.

The rise for the Greens follows a high-profile by-election breakthrough in Manchester last week. On 26 February, the Green candidate Hannah Spencer won the Gorton and Denton by-election with about 41% of the vote, pushing Labour into third place in what had been regarded as one of the party’s safest seats. The victory took the Greens to five MPs and delivered the party its first Westminster seat in northern England.

Anthony Wells, YouGov’s head of political polling, linked the Green surge to voters increasingly seeing the party as a viable choice. He said the change appeared to reflect “the Greens appearing to be a more viable option and less of a wasted vote”.

The latest poll suggests the Greens are now particularly strong among younger voters. Among 18–24 year olds, 49% said they would vote Green, according to figures cited by Sky News. Among those aged 25–49, the Greens were also the leading party on 27%.

The polling points to further fragmentation among people who backed Labour at the 2024 general election. Among 2024 Labour voters, 37% said they would vote Labour again, while 25% said they would now vote Green. A further 8% said they would vote Liberal Democrat, and 20% were undecided or said they would not vote.

The numbers are likely to increase pressure on Labour’s leadership over the party’s political direction, with the government facing challenges on both flanks: Reform continues to lead overall, while the Greens appear to be consolidating discontent on the left.

There was an immediate rebuttal from within government. Darren Jones, the Chief Secretary to the Treasury, described the Greens as “the populist of the left” and argued they did not have “credible plans”, in comments reported by Sky News.

The Green Party, meanwhile, sought to frame the result as evidence it is replacing Labour as the main vehicle for change. In a statement carried by Sky News, the party said: “Gorton and Denton showed that if people vote Green, they can get Green… voters want change and increasingly see the Greens as [the] party to break the failed status quo.”

The poll also comes amid wider political volatility, including heightened tensions in the Middle East and renewed debate about the UK’s stance on US-led military action involving Iran. The Financial Times has reported that dissatisfaction with Labour’s positioning on the issue has been a factor in the Greens’ recent momentum, noting that public support for the US offensive stood at 28%.

Economists and political strategists have also pointed to a difficult domestic backdrop for the government, with concerns over growth, unemployment and the tax burden fuelling voter restlessness. While no single poll can determine whether a change is durable, the pattern in this survey suggests the governing party’s coalition remains under strain, particularly among younger voters.

Reform’s 23% keeps the party in first place, though it is down slightly on YouGov’s previous reading and below peaks above 29% recorded last year, according to earlier reporting. Separate polling earlier this year by Ipsos had put Reform as high as 30%, underscoring the extent to which the right-of-centre vote has been reshaped since 2024.

For Labour, the immediate question is whether the Greens’ advance proves to be a short-lived post-by-election “bounce” or the beginning of a longer-term realignment. Further tracking polls over the coming weeks are expected to show whether the Greens can hold their gains and whether Labour can recover ground after being overtaken by a party that, until recently, had been a minor presence at Westminster.