Zack Polanski suffers heavy defeat in Holborn by-election, raising fresh questions about his future as Green leader - as ex-party MP fails to back him

Zack Polanski's leadership of the Green was plunged into fresh crisis tonight as a former party MP accused him of going 'missing' during the recent anti-Semitism row and refused to endorse him continuing in the role. 

Caroline Lucas, also a former party leader, castigated Mr Polanski in a TV interview for avoiding a weekend party conference vote that passed a highly controversial 'Zionism is racism' policy. 

After polls closed tonight in the Holborn & St Pancras by-election, in which he hopes to become the latest Green MP, she attacked him for fleeing the event in Brighton instead of staying and opposing the 'dangerous' move by hardline pro-Palestinians activists.

Party members on Sunday passed a motion that demands the eventual destruction of Israel, as well as treating it like apartheid South Africa over the war in Gaza.

But Mr Polanski left the event after giving a speech on Friday, to concentrate on his personal campaign in Holborn & St Pancras, where he is on course to lose to Labour.

Later, after the vote, he tried unsuccessfully to quell the uproar by joining the party's five MPs in releasing a statement distancing themselves from the decision. 

Speaking to the BBC's Newsnight tonight Ms Lucas, the former Brighton Pavilion MP, said 'he should have been there and he should have voted', adding: 'I would have hoped that he would have really been a very strong critic of this motion because the motion was flawed from top to bottom in my view. 

'It is dangerous, it is divisive, it tries to have a singular definition of Zionism when we know that there are many.'

Asked if he should carry on as leader she said: 'Let’s see what happens in the coming days and weeks.

Caroline Lucas, also a former party leader, castigated Mr Polanski in a TV interview for missing a weekend party conference vote that passed a highly controversial 'Zionism is racism' policy

The under-pressure 'eco-populist' is standing to replace Sir Keir Starmer in the north London seat but is forecast to be defeated by Labour's Sagal Abdi-Wali in the early hours

An unexpected win would make Mr Polanski the sixth Green MP in the Commons, but a defeat, especially a heavy one, will trigger fresh questions about the direction he has taken the party

'I want him to speak about what happened, I want him to show the leadership that was missing on Sunday, I think the jury is out about whether he will do that but I hope he will.'

The under-pressure 'eco-populist' is standing to replace Sir Keir Starmer in the north London seat but is forecast to be defeated by Labour's Sagal Abdi-Wali in the early hours of the morning. 

An unexpected win would make Mr Polanski the sixth Green MP in the Commons, but a defeat, especially a heavy one, will trigger fresh questions about the direction he has taken the party.

The party enjoyed a surge in the polls earlier this year but has seen itself slip backwards after a series of gaffes and the emergence of Andy Burnham as Labour leader.  

But it is the latest of several controversies the Greens have been mired in since the former actor and hypnotist took over in September last year, taking it further to the Left and away from its ecological roots. 

After the polls closed, a Conservative spokesman said: 'If Zack Polanski fails to win this by-election, it will surely be curtains for his leadership of the party. 

'We hope it also marks the end of the Green Party's sorry embrace of anti-Semitism.'

The Greens tonight suggested that just being the main challenger to Labour was an achievement.

Mr Polanski wrote on social media: 'The Green Party got 10 per cent last time. 

'Whatever happens tonight - we made Labour work like they never have before. I'm so proud of you all.'

The Green leader had been appealing for help from activists as residents cast their ballots in the contest for Sir Keir Starmer's old seat.

Ms Abdi-Wali is the bookies' favourite, with confidence growing inside the party that the Camden councillor will clinch victory.

Ms Abdi-Wali is the bookies' favourite, with confidence growing inside the party that the Camden councillor will clinch victory. 

But Mr Polanski insisted on social media overnight that he 'can win', claiming there might be just a 'few hundred votes in it'.

He pointed to a projection from Poll Check suggesting Labour could get 40.4 per cent of the vote and the Greens 35.6 per cent. 

Defeat for Mr Polanski would underline how Mr Burnham's arrival has flattened the Green surge – which saw them scoop Gorton & Denton in a by-election in February and then secure record-breaking local council results in May.

Holborn & St Pancras has been a Labour stronghold since its formation in 1983, held by Frank Dobson for 32 years and Sir Keir for 11.

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 per cent of the vote (18,884 votes), with independent Andrew Feinstein as runner-up on 18.9 per cent (7,312 votes) and the Greens in third with 10.4 per cent of the vote (4,030 votes).