Asked to reflect on what's gone wrong for the Greens, Polanski responds that if tripling their vote share and having their second best by-election result ever means things are going wrong for the Green Party, "then I'll take that".

"What was a safe Labour seat since 1983 is now a marginal Labour seat, that's clearly growth and next time we can get it over the line," he explains.

When pushed on the fact his own popularity has declined in the polls, Polanski says his mission has been to ensure Labour is "more scared" of the Greens than they are of Reform.

In fact, Polanski says, Prime Minister Andy Burnham has been using "a lot of the language and rhetoric" that he has been using over the past year.

Green Party leader Zack Polanski is speaking to BBC Radio 4's Today programme following his party's by-election loss in Holborn and St Pancras.

You can follow along by clicking watch live at the top of this page. We'll also bring you key updates here.

Phillipson is next asked about the Green Party vote declaring Zionism is a form of racism.

Asked whether she thinks the Greens have an "antisemitism problem", the Labour Party chair replies: "Yes, I think there is a serious challenge they face there."

She says Prime Minister Andy Burnham has been clear that the motion passed by Green Party members is "wrong", and has caused "real distress" for Jews.

"The Greens should distance themselves from it, you should hear Zack Polanski this morning condemning that motion and stepping away from it," she adds.

Earlier, Polanski said he wouldn't have voted for the motion in its current form.

Labour Party chair Bridget Phillipson is now speaking to BBC Breakfast.

The party is "absolutely delighted that we secured such a brilliant victory", she says, praising Sagal Abdi-Wali as an "amazing candidate".

Asked about the turnout in this by-election being lower than seen in the constituency during the 2024 General Election, Phillipson says "you would expect turnout to be low in a by-election" and says it's "still pretty decent" in the context.

She says that the result is "a real endorsement of Labour's message of "hope".

But she notes that "winning one seat isn't the same as winning 600-odd", and says the next election will be "a big fight for the future of our country".

"You can never be complacent in politics," she adds.

As we've just reported, Green Party leader Zack Polanski has told the BBC he wouldn't have voted for the motion that declared Zionism is a form of racism in its current form.

Polanski couldn't vote at the conference, as he was campaigning for yesterday's by-election, but he said he would have supported an amended motion, if that had been passed by party members.

After the motion passed by 1,022 votes against 813 last week, Polanski said he had wanted to see two amendments.

Firstly, the leader wanted to see the reference to a single Palestinian state changed, arguing: "I don't believe we as a Green Party of England and Wales, or even the British government, should be deciding what the future settlement looks like."

He had also said he wanted an amendment to specify that it should not be used to discipline Jewish members attending synagogues that consider themselves Zionist.

Both amendments were rejected by Green members.

There has been a lot of reporting overnight on this motion - passed by Green Party members at the party's conference in Brighton last weekend.

In this video, from earlier this week, our chief political correspondent Henry Zeffman explains what the motion is and the row surrounding it:

Zack Polanski is asked whether he agreed with the Green Party motion - passed recently at their conference in Brighton - that declared Zionism is a form of racism.

The Greens leader says he "grew up in a Zionist household" but now understands more about the displacement of Palestinians in the region.

"It's very obvious to me that if there is an ongoing genocide, then that is underpinned by a racist ideology," he explains.

Pushed further on whether he agrees with the motion, Polanski describes it as "imperfect" and agrees with some parts but disagrees with others.

For instance, he disagrees that the British government could decide there is a single state in the region, but agrees the "displacement and genocide" of the Palestinian people is underpinned by a "racist ideology".

Had he been present to vote, Polanski continues, he would have voted for an amended motion that removed the first element.

Green Party leader Zack Polanski is now speaking to BBC Breakfast.

He starts by saying he's "incredibly proud" of the campaign they ran in the Holborn and St Pancras by-election, and that the result shows that his party is "more of an electoral threat in these seats than we've ever been before".

"This is the foundation we're looking to build on," he says.

Polanski says that the main reason he thinks he didn't win the seat is because people have told him they like the party's policies but want to "give Andy Burnham a chance" as prime minister.

"Well, Andy Burnham's got a chance now, let's see what he does with it," he says.

• You can watch Polanski speaking to BBC Breakfast at the top of this page

Polanski is dealing with the greatest crisis of his leadership so farpublished at 06:29 BST

06:29 BST

Chris Mason
Political editor

In the aftermath of a by-election, the focus is usually on the winner. Not this time.

Make no mistake, the new MP for Holborn and St Pancras, Sagal Abdi-Wali, has quite the personal story to tell.

But in the offices of Camden Council at 03:00 this morning, the focus of the press pack, me included, waiting for the declaration was on Zack Polanski.

Defeated, yes, but – more significantly – confronting a wall of questions about his party, his leadership, his judgement, his future.

He’s swerved these questions for days and is now facing up to them as he attempts to deal with the greatest crisis of his leadership so far.

From open, public insurrection from senior figures internally to opprobrium, contempt, disgust from plenty of others beyond the party.

Polanski remains defiant. He insists the displacement of Palestinians is racist, as he puts it, and no one will be excluded from the Green Party of England and Wales based on their religion.

“Of course I can carry on,” he said.

Any leader having to answer that question in public knows the pressure they are under.

Labour won Thursday's by-election, securing 12,292 votes overall.

Despite the Green Party originally saying while conceding that it had come in "a close second" in the vote, Labour's Sagal Abdi-Wali ultimately achieved over 3,000 more ballots than Zack Polanski.

The third place candidate, Ewan Cameron of the Conservatives, received 1,922 votes, followed by Reform's Pete Newman in fourth and Patrick Stillman of the Lib Dems in fifth.

Joe Coughlan
Live reporter

Image source, PA Media

Labour's Sagal Abdi-Wali has claimed victory in the Holborn and St Pancras by-election, retaining the party's seat in a vote which was seen by many as an opportunity for Green leader Zack Polanski to enter Westminster.

If you're just joining us, here's what you need to know:

• Abdi-Wali secured 12,292 votes, fending off Polanski's 8,928 in a poll which was triggered by the resignation of Keir Starmer from the Labour stronghold seat
• The Camden Council leader said she was honoured to represent the constituency while touching on policies such as homelessness and nationalising Thames Water in her victory speech, saying: "People need to believe that politics can make their lives better"
• Polanski's loss comes amid criticism of his party's Zionism motion at its conference last weekend - his interview this morning is the first time he's answered questions on the matter
• Despite his by-election loss, the Green leader has said he will "of course" remain in his role - our political correspondent Jack Fenwick speaks of the pressure he may face ahead of the next election
• The Conservatives came third in the by-election, claiming 1,922 votes, with Reform UK, the Lib Dems and Restore subsequently following
• Thursday's vote saw a turnout of 38.76%, marking a decrease when compared to the 2024 general election

A further look now at some of the numbers from this morning's by-election result.

Labour's Sagal Abdi-Wali secured 45% of the vote, down four points on the party's result in the general election two years ago.

The Greens got 33% of the votes, up 22 points on their 2024 results.

The Conservatives and Reform UK performed similarly to two years ago, while the Lib Dems' vote share was down two points.

Sagal Abdi-Wali says her victory in the by-election shows the people of Holborn and St Pancras are "looking for hope".

The newly elected MP says the result speaks to the fact that people want to bring Thames Water into public ownership and bring more opportunities for young people - two topics she campaigned on.

She tells BBC News she has "already" been having conversations with Prime Minister Andy Burnham on those subjects.

Regarding the Green Party saying its performance in tonight's vote shows it is making inroads, Abdi-Wali says voters were "really responsive" to the message Labour was putting out: "The Greens can do what they want."

When asked if she believes the recent Green Party motion on Zionism had contributed to her victory, she said she does not believe so but constituents had spoken to her about how "scared they were" by it.

Labour has never lost Holborn and St Pancraspublished at 04:59 BST

04:59 BST

By Daniel Wainwright

When former prime minister Keir Starmer was last elected as the MP for Holborn and St Pancras in 2024, he got 49% of the vote.

His highest vote share in the constituency came in 2017, when seven in 10 votes went to Labour.

Labour has held this seat since it was created in 1983, although it has changed shape over time because of boundary changes.

The lowest vote share Labour has recorded came in 2005, when the then-MP Frank Dobson won 43% of the vote, but still had a majority of 4,787 over the second placed Liberal Democrats.

Difficult questions for the Greens aren't going awaypublished at 04:42 BST

04:42 BST

Jack Fenwick
Political correspondent at the Holborn and St Pancras by-election

Zack Polanski’s interview with broadcasters this morning is the first time he’s answered questions about the Green party’s new policy declaring that Zionism is racism.

Asked if he agreed with it, Polanski said the displacement of the Palestinian people was racist.

But he still didn’t come down firmly on one side or the other when it comes to the specifics of the motion that Green members backed on Sunday.

Those who were supportive of the motion wanted Polanski to come out and explicitly declare it was now party policy.

Those against it wanted him to distance himself from the motion and make it clear that he didn’t support it.

Polanski will hope that by not doing either he may have taken some of the heat out of the situation.

But there’s a danger from him that he annoys both sides.

He insists he’s staying on as party leader after this defeat, but the difficult questions from inside the Greens aren’t going away.

Read more in our full story here, external

Image source, Reuters

How Holborn and St Pancras voted in May’s council electionspublished at 04:27 BST

04:27 BST

By Daniel Wainwright

Before this by-election, the most recent vote held in Holborn and St Pancras came in May’s local council elections, which saw Labour lose 17 seats on Camden Council but retain overall control.

Councils and parliamentary constituencies have different boundaries, but we have compiled the vote share for the council wards that make up Holborn and St Pancras.

Labour won the largest share of the vote in the council elections among people in the constituency.

Just under 40% of votes went to Labour for seats on Camden Council, with the Greens on just under 30%.

Across Camden overall, Labour won 30 of the 55 seats, a loss of 17, while the Greens gained 10 seats to reach 11 overall. The Liberal Democrats also increased their seats from four to 10 and the Conservatives stayed on three seats.

But it’s worth bearing in mind that Camden Council has a different voting system to that used tonight.

There is more than one councillor per ward, so people voted for either two or three candidates, depending on where they lived.

Polanski will be under pressure to outline where party can make gains at next electionpublished at 04:21 BST

04:21 BST

Jack Fenwick
Political correspondent at the Holborn and St Pancras by-election

This was always going to be a tall order for the Green Party, but Zack Polanski will nevertheless be disappointed with the result.

A few months ago, when his party was riding high in the polls and Labour had a very unpopular prime minister, he may have had more of a chance.

But the Greens have dipped more recently - and that trend has continued since Andy Burnham became PM.

The Greens say this was evidence of them catching up with Labour. But some of those who had already been quietly asking questions of Polanski may now get louder.

He’ll be under pressure to outline where, if not here, the party hopes to gain seats at the next election.

For Labour, their vote share did go down and there are still questions about whether the party is as popular as it was at the general election two years ago.

But if Andy Burnham’s victory in the Makerfield by-election was evidence that he was able to beat Reform, to Labour’s right, those around the PM will absolutely say this is evidence they can beat the Greens, to Labour’s left too.

Tara Mewawalla
Reporting from the Holborn and St Pancras by-election

Image source, Reuters

A significant amount of Sagal Abdi-Wali’s speech centred on homelessness, opportunities for young people, belonging and diversity.

The message of “hope” was central to her campaign, and reiterated in her victory speech.

“For all people, but especially for young people, I want this to demonstrate that you do not have to surrender your hope to succeed," she said.

Her pride in becoming the first woman to represent Holborn and St Pancras was also clear, and was met with cheers from supporters in the counting venue.

So too was her belief that in Camden “our diversity is a strength”.

“Our cohesion has been too hard won to take for granted,” she added, to audible support from party members.

Susana Mendonca
BBC London

Labour members were jubilant as Camden Council’s leader Sagal Abdi-Wali became Holborn and St Pancras’ latest MP.

She spoke of her “pride and humility” following the legacy of the previous MPs here: Keir Starmer and Frank Dobson.

She said the diversity of the constituency was a strength.