In Highgate New Town, a north London housing estate whose brutalist architecture has been a fixture of film shoots, the enormous scale of the challenge Labour faces in the capital from the Greens was starkly evident.

But Camden – a diverse borough with some of London’s most affluent neighbourhoods as well as pockets of deprivation – carries particular symbolism: it is home to Keir Starmer’s own constituency of Holborn and St Pancras.

Labour activists knocking on doors across the borough report being regularly confronted with Starmer’s unpopularity – one activist confessed to being taken by surprise at the sometimes “visceral” attitude. But they also face the usual anti-incumbent mood and local concerns.

Boampong, a council tenant and former London bus driver still working for TfL, cited a lack of bins for food recycling and what she saw as the failure of the council to respond to a problem of a leaking boiler. “I did tell Labour, who were here earlier, that they had lost four votes in this home,” she said.

Russell, a former Labour councillor, said the “Zack bounce” had helped the party, but the Greens were benefiting as much from grassroots efforts to champion the concerns of local people – including a recurring theme of problems around housing maintenance – as wider issues such as Gaza.

“We’ve been clear about standing up for peace and human rights, including speaking out on Gaza. But the Muslim households I speak to are often just as concerned about day-to-day realities they’re living with, like overcrowding housing conditions, damp and mould,” she said.

“I can’t stop a genocide on my own, but I can make a real difference here by tackling those problems and making sure people have decent homes.”

A wider fragmentation of the progressive vote across London is also reflected in Camden amid a fight for control of the council by the Greens, Liberal Democrats and Labour – which holds 45 of its 55 seats – as well as independent candidates.

It would require a uniform swing of 19% to another party for Labour to lose its majority, though there is a high element of unpredictability in a race where five parties are fielding an almost full slate. Another unknown is how much accusations of antisemitism will hurt Polanski’s party.

But the rise of the Greens in inner London – more even than the prospect of Reform UK taking seats in Havering and Bexley – has shot a shiver of alarm through the Labour party.

The capital’s 59 Labour MPs have several cabinet ministers in their ranks – David Lammy, Wes Streeting and Steve Reed, along with Starmer. Most have been used to safe five-figure majorities where the MPs rarely felt at risk. But the London local elections suggest all of that could change.

Although the Tories also anticipate tough results, they could retake control of Wandsworth council and make gains in Westminster, allowing Kemi Badenoch to channel Kenneth Baker, Margaret Thatcher’s party chair, who in 1990 pointed to victory in the two notable councils as a way of spinning defeat elsewhere.

Labour – on course for its lowest ever vote share in London, worse even the 28.3% delivered by Harold Wilson in 1968 that left his party controlling just three of the 32 councils – could struggle to find a similarly symbolic success story.

Polling for More in Common suggests that Labour’s vote share has fallen 15 points in London since 2024, with the Conservatives down four points.

That support has been seized almost entirely by smaller parties: Green support has increased by 10 points, while Reform UK are up six points.

The Lib Dems, meanwhile, are the only traditional party that looks like it will avoid the fate of the mainstream, holding comfortable leads in their south-west London strongholds and challenging Labour in Merton.

While Labour’s dominance means there is further for it to fall, it also makes it harder for its opponents to win councils outright. Several in the capital could end up in no overall control, presenting a quandary for how they are run.

Prof Tony Travers, a local government expert at the LSE, said: “Stitching together a way of governing could give us a clue to what might happen at the next general election, where there is a real possibility that deals will have to be made.”

There will be a direct impact on Starmer that stretches beyond what unfurls in his own back yard. With 1,150 of the 2,500 council seats that Labour is defending in the capital, it will be a litmus test of whether the party can hold even safe areas with him at the helm.

If its MPs conclude not, then more may join those on the backbenches already agitating for change.

Back in Camden, such is the pressure that the Labour leader of the council, Richard Olszewski, has switched to running for a different seat – in what opponents deride as a “chicken run” – because he would not have the time to defend his previous one from the Lib Dems.

He conceded that Labour faced a huge challenge, pointing out that the two occasions on which the party had lost Camden in the last 60 years was in the depths of unpopularity in the late 60s and in the aftermath of the Iraq war, when he was a special adviser in the Blair government.

“We’re not immune to the dynamics that are going on nationally,” he added.

“On the doorsteps we do encounter voters who might be critical of Keir Starmer, and we make the point, not facetiously, that he isn’t standing here. It’s about who runs the council and we’ve got three outstanding ratings for our services.” Labour is hoping that will be enough.