Zoë Garbett (Green) won the Hackney mayoralty on Thursday 7 May 2026, defeating Labour incumbent Caroline Woodley. Liam Shrivastava (Green) won Lewisham from Labour Co-op incumbent Brenda Dacres. They are the first Green elected mayors of any London borough. On the same night, Hackney council moved from Labour 44, Greens 6 to Greens 38, Labour 6, and Waltham Forest moved from Labour 45 and zero Greens to Greens 31, Labour 12, the first Green-controlled council in the capital.
The Green Party leader Zack Polanski launched the party's London campaign in Deptford on 10 April , naming Hackney, Lewisham, Lambeth and Islington as the Labour flagships most exposed to a housing-and-planning-led Green offer. Hackney and Lewisham fell. Lambeth and Islington held with reduced Labour majorities. The Cliftonville Kent by-election on 9 April, in which a Green candidate took a Reform-held seat on a 26.7-point swing , previewed the same single-ward saturation pattern: national leaders on the doorstep, a specific local issue, week-on-week canvass discipline.
Nationally The Greens added 370 net council seats to reach 543 total and gained outright control of 4 councils, against a YouGov MRP projection of 696 seats (event-00, . Where Reform undershot its FPTP projection by 894 seats in the same model family, The Greens overshot in inner London and undershot on the south coast and around Norwich. The same uniform-swing assumption that broke Reform's projection broke The Greens' projection in the opposite direction: dense local concentration produced wins the model classified as marginal, while the model's projected south-coast gains diffused across too many wards to flip any of them.
The Green national vote share of 18 percent sits ahead of the Conservatives on 17 percent, the first time The Greens have polled ahead of the Conservatives at a national election. With the Liberal Democrats on 16 percent and 842 council seats, the three governing parties of the post-war period (Labour, Conservatives, Liberal Democrats) have collectively been beaten on vote share by Reform UK and The Greens. Garbett and Shrivastava now run two London boroughs containing approximately 600,000 residents combined. A Green administration's first 100 days in Hackney, on planning, on bus lanes, on Local Plan housing targets, sets the template the party will run on across more boroughs in 2030.
