Labour has been warned it could suffer an extraordinary reversal in the capital at the 7 May London borough elections, with new campaigning data and modelling suggesting the party could be left in control of as few as two councils.

The projections, reported by GB News, are based on internal and party-commissioned assessments of the London battleground ahead of polling day, when all 32 borough councils will be contested — around 1,800 seats in total. If borne out, the result would represent one of the most dramatic shifts in the political map of London in decades and an early electoral shock for Prime Minister Keir Starmer less than two years after Labour’s general election victory.

The warning comes as Labour faces pressure from both sides of the political spectrum in London: the Green Party, which is targeting inner-city Labour heartlands, and Reform UK, which is seeking to build support in suburban and outer-London boroughs.

Tony Travers, professor of local government at the London School of Economics, has warned that the capital could be heading for a “political earthquake”, a phrase that has been repeatedly used in recent days as parties prepare for the May contest. Travers has pointed to signs of weakening Labour support in boroughs including Camden, Islington, Hackney, Newham, Lewisham, Southwark and Lambeth, according to reporting in the Evening Standard.

The Greens, led in England and Wales by Zack Polanski, have been increasingly explicit about their ambition to break Labour’s hold on progressive parts of the capital. The party is focusing resources on inner-London areas with large younger electorates and strong pro-environment sentiment, with Hackney and Lambeth among the boroughs being spoken about as prime targets.

Reform UK, led by Nigel Farage, is meanwhile seeking to convert its national momentum into council gains in London’s outer ring, where issues such as the cost of living, local services and perceptions of Westminster politics have fuelled volatility. Analysts have suggested boroughs such as Bexley and Bromley could be areas of opportunity for Reform, while Barnet has also been mentioned as a competitive contest in a fragmented field.

The latest modelling is being interpreted by Labour figures and observers as further evidence of a widening problem: erosion of support on Labour’s progressive flank, with voters moving to the Greens, alongside a separate challenge from Reform in parts of outer London.

Those concerns were sharpened by the February parliamentary by-election in Gorton and Denton, where Labour fell to third place behind the Greens and Reform. In that contest, the Greens’ Hannah Spencer won with 14,980 votes (40.7%), Reform’s Matthew Goodwin was second with 10,578 (28.7%), and Labour’s Angeliki Stogia took 9,364 (25.4%), according to AP. The seat had been regarded as a long-running Labour stronghold, and the outcome has been treated by rivals as a sign that traditional voting patterns are becoming less reliable.

While parliamentary by-elections can produce unusual results, strategists in multiple parties have argued that the Gorton and Denton vote showed a particular vulnerability for Labour: a growing pool of voters willing to move left to the Greens or to cast a protest vote for Reform, depending on local conditions and candidate appeal.

London’s borough elections are also taking place in a wider national context that is expected to heighten scrutiny of the results. The 7 May voting day coincides with elections for the Scottish Parliament and the Welsh Senedd, making it the biggest set of polls since the 2024 general election.

Labour’s starting point in London is strong on paper. The party dominated the 2022 borough elections and has for years been the principal governing force across much of the capital, particularly in inner London. However, the current projections suggest that borough-level dominance could be at risk if Labour’s vote fragments across a wider set of parties — with the Greens, Liberal Democrats, Conservatives and Reform all competing for different parts of Labour’s 2022 coalition.

Some Labour insiders have privately characterised the threat as a two-front squeeze: losses to the Greens in areas where voters are pushing for more radical action on housing, climate and public services, alongside losses in outer boroughs where Reform is attempting to position itself as an anti-establishment alternative.

The Greens have sought to frame the election as a chance for progressive voters to “send a message” to Labour, arguing that London’s politics is moving toward a more plural landscape in which the party can no longer assume automatic support in its strongest areas. Reform, for its part, has argued that dissatisfaction with established parties cuts across traditional left-right lines and that local elections are a key opportunity to translate national visibility into seats.

The stakes for Labour are not limited to the number of councils controlled. Boroughs run major services including housing management, social care, planning and local transport priorities, and London’s councils have long provided Labour with a base of elected representatives and organisational strength.

A result approaching the most severe scenario outlined in the new modelling — Labour retaining control of only two boroughs — would immediately raise questions about the party’s standing in the capital and the resilience of its electoral coalition, as well as the wider political direction of the country under Starmer.

As of this weekend, no official forecasts exist for borough-level outcomes across London, and party modelling can be wrong, particularly in elections affected by turnout swings and localised campaigning. However, the language being used by analysts and within party circles underlines the extent to which even long-held assumptions about London’s political makeup are now being contested.

Labour, the Green Party and Reform UK have been approached for comment.