Labour has held the Holborn and St Pancras parliamentary seat in central London, defeating a high-profile challenge from Green Party leader Zack Polanski in a byelection that was seen as a test for Prime Minister Andy Burnham. Labour's Sagal Abdi-Wali, leader of the local Camden council, won 12,292 votes (45%) to Polanski's 8,928 (33%). Turnout was 38.7%, the lowest for any English byelection in this parliament and 15.4 points lower than at the 2024 general election.

The seat was vacated by Keir Starmer, who stepped down as an MP in September after being replaced as prime minister in July. Starmer had lost the support of his party after a series of U-turns and poor local election results in May, when the Greens made record gains in London, largely at Labour's expense. The contest was considered a two-horse race, with the Greens sending thousands of members to knock on doors.

In an emotional victory speech, Abdi-Wali, who came to the UK from Somalia as a child refugee in the 1990s, criticised "those who seek to divide us", in what appeared to be a response to Reform UK's Zia Yusuf, who suggested shortly after the byelection was called that she was not British. "This is Camden and this is Britain," she said. She also said local voters had found the Greens' recent Zionism motion divisive.

That motion, passed by Green members at their conference on Sunday, said Zionism should be "treated as any other form of racism". It drew criticism from Jewish groups, other parties and four of the party's five MPs. Polanski, who is Jewish, abstained and campaigned in the constituency instead. Former Green leader Caroline Lucas said she wanted him to show the leadership that was "missing on Sunday". After the result, Polanski said he would remain leader: "I've taken a loss tonight but our movement is so much bigger than one election or one motion." He said the displacement of Palestinians was racist, but did not say he supported the motion.

The Greens presented their result as a sign of progress, citing a 22% rise in vote share. Polling expert Peter Kellner called that misleading, noting that in 2024 the left vote was split between the Greens (10.4%) and independent Andrew Feinstein (18.9%), who this time backed Polanski. Combined, the Green and left vote fell by more than 2,000 votes. The BBC's Sir John Curtice said Labour is in a better position than six months ago but not as popular as in 2025, and that the Greens have lost much of the ground gained in Polanski's first year as leader.

Why it matters: the result gives Burnham reassurance in his first major electoral test, and supports polling suggesting he has won back some left-leaning voters through a tougher line on Israel and closer ties with the EU. But the low turnout suggests Labour still faces a challenge in urban areas, particularly London. Nationally, Reform UK remains Labour's main rival in polls, with the next general election due by mid-2029.