Zack Polanski’s Green Surge Threatens Labour in London
Polanski is turning the Greens into a London insurgency, but antisemitism rows could blunt gains in Thursday’s council vote.
Zack Polanski is trying to turn a fast-rising Green Party into a serious London force, with YouGov modelling cited by 
Al Jazeera and 
POLITICO projecting the party could come first in multiple boroughs in the capital on 7 May. That would not just be a local upset. It would confirm that the real contest in urban England is no longer just Labour versus Conservatives, but Labour versus insurgents on both flanks.
Why Polanski matters
Polanski, 43, won the Green leadership in September 2025 by a landslide and has recast the party around what he calls “eco-populism”: higher taxes on the wealthy, stronger workers’ rights, rent controls, and a harder anti-establishment pitch on housing and cost of living, Al Jazeera reported. The Greens then won their first parliamentary by-election in February, taking Gorton and Denton from Labour, and have since looked like more than a protest vehicle, according to 
BBC. That matters because it gives the Greens a claim on Labour’s old terrain: younger voters, renters, and urban progressives who still want redistribution but no longer trust Keir Starmer’s Labour.
Labour’s problem is not just the Greens
The Greens are benefiting from fragmentation. In London, BBC says the capital could become a “political patchwork quilt,” with Labour, Conservatives, Greens, Reform UK and independents all competing to run boroughs. POLITICO says the Green vote is concentrating in inner London boroughs such as Hackney, Lambeth, Lewisham and Waltham Forest, where Labour has long relied on progressive loyalty.
That is the power dynamic Polanski is exploiting: Labour is squeezed by a left challenge that looks socially liberal and economically left-wing, while Reform UK pulls outer-borough protest voters in the opposite direction. Tim Bale of Queen Mary University told Al Jazeera that the Greens are now “far more left-liberal and pro-Gaza focused,” with Polanski’s visibility amplified by frustration with Labour’s rhetoric on immigration. The result is bad news for Starmer: even if the Greens do not win many councils outright, they can strip Labour of the margins that keep London red.
What could stop the breakthrough
Polanski’s momentum is not clean. Al Jazeera says his campaign has been hit by a row after the Golders Green stabbings, while 
The National reported Labour’s last-minute dossier accusing Green candidates of antisemitic and conspiratorial posts. That gives Labour an opening to turn the election into a judgment on competence and discipline, not just anger at Starmer.
What to watch next is simple: whether Polanski can convert vote share into council control, not just councillors, and whether the Greens’ London advance survives the final-day backlash. If they do, the bigger story is not one Green leader. It is that Labour’s urban coalition is now being pulled apart by rivals who understand local anger better than Labour does.
