Zack Polanski today admitted he was wrong to claim he was a spokesman for the British Red Cross.
The Greens leader backed away from the false claim - made during his 2022 campaign to become the party's deputy - as he faces increasing scrutiny ahead of local elections.
Mr Polanski was also grilled on his post endorsing criticism of the police forcibly detaining the Golders Green knife attack suspect last week. The London Assembly member said he had been 'traumatised' by the footage.
He also suggested that the issue of Palestine is 'on the ballot' for the wave of English council elections tomorrow.
Political opponents had demanded Mr Polanski 'comes clean' and corrects the record about his British Red Cross claim - which was highlighted by The Times overnight.
Zack Polanski today admitted he was wrong to claim he was a spokesman for the British Red Cross
A poll released yesterday suggested Mr Polanski's personal rating have slumped over the past week
Asked about the issue in an interview on BBC Radio 4's Today Programme, Mr Polanski said: 'I hosted various fundraisers for the British Red Cross, and indeed I would go on stage and speak for them about the amazing work they do tackling humanitarian crises, on the climate crisis, and indeed, for refugees all around the world.
'I used the wrong word, and I accept that, but I would essentially take words on stage with me and speak.
'It's important, though, and I accept this, that they don't support any political party, and I've made sure that's been taken down.'
The Green Party leader was condemned last week for endorsing claims on social media that Metropolitan Police officers were heavy-handed after three people were stabbed, earning a public rebuke from Commissioner Sir Mark Rowley.
He faced barbs from within his own ranks, as well as from Keir Starmer who branded him 'disgraceful' and 'not fit to lead any political party'.
Mr Polanski issued a half-hearted apology on Friday night, but in a round of media interviews on Sunday doubled down on questioning the police's actions.
Mr Polanski said today that he had reposted messages criticising the police's use of force because he was 'traumatised'.
He said: 'Two things can be true at the same time: officers are incredibly brave when they run towards scenes of crimes that most people, including myself, will want to run away from.
'At the same time, I think it is accurate, and that I was also traumatised by seeing someone handcuffed and repeatedly kicked in the head.'
Labour has been targeting the Greens heavily in campaigning for the local elections, highlighting alleged 'disturbing' views held by some candidates.
Mr Polanski came under fire from a predecessor as Green leader yesterday for failing to tackle anti-Semitism within the party.
Former Brighton MP Caroline Lucas, who led the Greens three times between 2003 and 2018, said 'immediate action' was needed against local election candidates who had made 'unacceptable' statements.
She went public on X hours after Mr Polanski had accused his rivals of launching 'desperate' attacks because the 'hate our plan to end Rip Off Britain'.
Research by More in Common has suggested Mr Polanski's clashes with Scotland Yard might have harmed his standing.
The Green leader's personal ratings have tumbled 14 points over the past week, leaving him with a net score of minus 27.
The latest poll, conducted between May 1 and 4, suggests Mr Polanski is still performing better than Sir Keir, who has a dire rating of minus 45.
However, he is significantly less popular than Kemi Badenoch, Ed Davey and Nigel Farage.