Voters will go to the polls on Thursday as candidates compete to replace Sir Keir Starmer as MP for Holborn and St Pancras.
The North London constituency has been a Labour stronghold since it was created in 1983, held by Frank Dobson for 32 years and by Sir Keir for 11.
Green Party leader Zack Polanski is among those running, hoping to break Labour's run and secure his own seat in the House of Commons.
Green leader's defining moment
The by-election could be a defining moment for Mr Polanski's leadership, following a surge in membership and record results in the May 2026 local elections, when the party gained more than 440 councillors and took control of five councils.
It has been a difficult week for Mr Polanski, however, after the Green Party passed a controversial motion at its conference in Brighton asserting that “Zionism is racism”.
Mr Polanski, who abstained on the vote, later said he will “not accept any exclusion, or refusal to engage with anyone, because of the religious or communal body they are part of”.
Candidates make their case
Ahead of polls opening on Thursday, Mr Polanski said: “The election is looking close today. We already have a Labour government, a Labour council and a Labour mayor.
“Isn't it time for a Green voice for Camden to push Labour to do better on issues like rent controls and to put Thames Water into public ownership – issues where they've been backtracking?
“On the climate crisis, today is the day to say clearly to Labour, 'no new drilling in the North Sea' – a decision they chose to delay until after the by-election result. That makes your vote powerful.
“A vote for the Greens today can show Labour the right direction. Make it happen today.”
Labour's candidate is Camden Council leader Sagal Abdi-Wali, who is the bookies' favourite to win.
Prime Minister Andy Burnham said: “Today, hope can win. But only if you vote for it. I have no doubt that Sagal Abdi-Wali will make a brilliant local MP for Holborn and St Pancras.
“This area gave Sagal a home when she arrived here as a refugee in the 1990s. Camden gave Sagal and her family hope. Now she wants to give that back to the communities that have always been there for her.
“It's hard to think of someone more committed to their local area and the care of people than Sagal.
“Sagal has a plan to take on vested interests in our water industry, to work with me to help end rough sleeping, and to make sure every young person has the opportunities they deserve to get on in life.
“Sagal is bursting with energy and positivity. She's given so much to Camden already, and I know she has so much more to give. For Camden, for hope, vote for Labour's Sagal Abdi-Wali today.”
Full field of candidates
There are 13 other candidates in the by-election, including the Conservatives' Ewan Cameron, Reform UK's Peter Newman and the Liberal Democrats' Patrick Thomas Stillman.
Also running is George Galloway of the Workers Party of Britain, despite living overseas in what he describes as “self-exile”.
Sir Keir won the Holborn and St Pancras seat in 2024 with 48.9% of the vote (18,884 votes), with independent Andrew Feinstein as runner-up on 18.9% (7,312 votes) and the Greens in third with 10.4% of the vote (4,030 votes).
