Jennie Formby, Labour general secretary from 2018 to 2026, has joined the Green Party as polls indicate potential large gains for Zack Polanski in London
The political landscape in London is shifting as Jennie Formby, who served as Labour general secretary from 2018 to 2026, announced she will be campaigning for the Green Party ahead of the local elections on May 7. Her move follows a personal trajectory from voting Green in 2026 to becoming a formal member four months ago, and reflects wider turbulence on the left as voters and former officials reassess allegiances.
Formby has cited concerns about Labour‘s direction under Keir Starmer, accusing the leadership of abandoning pledges and being overly influenced by corporate backers.
Formby told national media that the Greens, led in the capital by Zack Polanski, are willing to foreground issues of economic justice and support measures such as tax changes and expanded workers’ rights.
Her comments underscore a wider argument from critics who say Labour has moved away from some of its traditional commitments. Labour sources have pushed back, arguing that only their party offers the credible program to lift hundreds of thousands of children out of poverty, deliver the biggest upgrade in workers’ rights for a generation, and revive public services.
What the polls are showing
Multiple surveys suggest the Greens are making measurable inroads across London. An Ipsos poll of adults in areas holding local elections found the Greens registering the highest level of consideration among voters, with Labour in second place on 44 per cent. The same research highlighted the issues driving choices: 62 per cent named the cost of living as a very important factor, followed by 58 per cent who put crime and policing at the top, and 54 per cent focused on the NHS. The Ipsos poll interviewed 1,600 adults between April 2 and April 8 in constituencies where local elections are due, offering a snapshot of voter sentiment ahead of the ballots.
Borough-level dynamics and methodology
A separate modelled poll (an MRP poll) produced by JL Partners points to more granular outcomes: the Greens are on slightly more than 40 per cent in Hackney with Labour just under 33 per cent, and in Haringey the parties were recorded at 30.4 per cent for the Greens and 28.2 per cent for Labour. That model also suggests Reform UK could carry Outer London boroughs such as Havering, where Reform registers about 30.1 per cent, and may be competitive in places like Bexley and Barking and Dagenham. Analysts caution that ward-level contests can hinge on small vote differences, but the pattern points to a potentially disruptive result for traditional parties.
Why voters are volatile
Polling evidence captures a wider appetite for change. Many Londoners appear willing to consider different options: the Ipsos study showed that 57 per cent expect Labour to lose seats, while 51 per cent believe the Greens will gain. The factors listed by respondents underline the practical concerns driving decisions: public transport and housing (44 per cent), education and schools (42 per cent), and local services including roads and pavements (50 per cent). These priorities create openings for parties that present clear, focused offers on everyday quality-of-life and cost pressures.
Political reactions and wider implications
Labour has responded to defections and poll volatility by stressing its program to support working families, expand rights, and build homes, arguing that the Greens supply the wrong answers on areas such as development and clean energy at scale. Meanwhile, the Greens celebrate the momentum and the willingness of some voters to switch from other opposition parties — a dynamic that could further erode Labour’s dominance in boroughs where margins are tight. More than 50 former Labour representatives have reportedly joined the Greens since the 2026 general election, a statistic that signals organisational as well as cultural shifts inside local politics.
What to watch before May 7
The coming weeks will test whether the polling snapshots translate into actual council control changes. Observers will monitor turnout patterns, tactical voting, and ward-level campaigns where small swings can determine control. For Labour, the risk is losing its status as the top vote-getter in multiple boroughs — a scenario that polls have flagged could affect up to 14 councils in London. For the Greens and Reform UK, the prize is historic gains and the legitimacy that comes with running councils. Whatever happens, the contest is likely to reshape local politics in the capital and provide signals about party trajectories ahead of future national contests.
