When Ken Livingstone made his statement about Hitler's passion for Zionism (before insanity turned him to the path of genocide) I was both surprised and not surprised at all. Not surprised, because I had heard him express these views before and dismissed them as the ramblings of an increasingly desperate and bitter man.

But I was surprised, still, that Mr Livingstone's judgement had diminished to such an extent that he had chosen to make repeated public statements on a subject that he had only previously spoken about privately.

I was taken back to six years ago when I went for a coffee with Mr Livingstone in the British Museum. He had just decided to run against Boris Johnson for a second time in the 2012 mayoral elections and had been advised to make nice to the Political Editor of the Jewish Chronicle, the job I held.

The encounter is seared in my memory because of what the former mayor of London said to me that day.

What started as a casual discussion soon turned into a lecture and then open insults. Mr Livingstone began by referring to a documentary I had made about him during his previous, doomed, run for office in 2008 and work I had done on the rise of radical Islam in the UK. "You are one of those writers who began on the left and then drifted to the right," he said. I told him I didn't accept his sweeping categorisation of writers who challenged his stance on extremism as Islamophobic. This was not just insulting and inaccurate, but potentially dangerous.

He dismissed my concerns and embarked on a rant about how he knew I had made the journey from left to right when I ended up at the JC. I was open-mouthed when he linked the paper in a circuitous and incoherent argument to "CIA money". Thinking back, I guess he meant that the JC's commitment to Zionism made it, by its very nature, part of the propaganda arm of American imperialism.

It was then that he launched into a discussion of Zionism itself. He mentioned Lenni Brenner, an obscure American Trotskyist I confessed I hadn't read, and his work on the historical links between Zionism and Hitler. "What you have to realise is that there were close links between the founders of the state of Israel and the Third Reich," he said.

I remember looking around me and hoping no one was listening. The CIA, Zionism, Hitler: I was being cornered by every conspiracy theorist I had ever met in the form of one of the most recognisable figures in political life.

I had once been impressed by Livingstone's maverick "rainbow coalition" politics but the final scales dropped from my eyes. His hostility to Israel and Zionism was, I felt, visceral. He was dripping with hatred and rancour that went beyond a concern about Israeli human rights abuses (in fact he didn't once mention the suffering of the Palestinian people).

I don't know if Mr Livingstone is a Jew-hater. I can't see into his heart, but that day I felt there was something that made a chill run up my spine.

Whoever it was in Jeremy Corbyn's office that saw fit to bring Ken Livingstone back into the political mainstream clearly didn't feel the same way. Whether it was Simon Fletcher, Mr Livingstone's former fixer in City Hall who now runs Mr Corbyn's operation, or the Labour leader himself, it has proved a catastrophic decision.

Mr Livingstone is not a man who can be controlled and he has redefined the meaning of loose cannon since his appointment (and then withdrawal from) the party's defence review. Indeed, it has been unclear for some time precisely what his role is beyond appearing on broadcast outlets to say outrageous things.

Only John McDonnell, Mr Livingstone's former colleague on the Greater London Council, seems to have got the measure of the man.

The de facto Deputy Leader is furious at the long leash given to Mr Livingstone and has been expressing his concern about the mental health of the man once famed for the sharpness of his political brain. Within Mr Corbyn's inner circle, speculation has mounted as to the reasons for Mr Livingstone's apparent increasingly slurred and repetitive delivery.

It may surprise readers of this newspaper, but there are those in the offices of the Labour leadership who are concerned about antisemitism in the party and the damage being done to the relationship with the Jewish community. These include chief of staff Simon Fletcher, John McDonnell and Mr Corbyn's son Seb, who runs Mr McDonnell's office.

The problem has been Jeremy Corbyn himself, who has repeatedly refused to address the issue, despite being warned from the moment he won the leadership election. Mr Corbyn did not see this crisis coming or even see it as a crisis when it arrived, precisely because antisemitism is a blindspot to him.

It took Jeremy Corbyn two working days from the time of Ken Livingstone's interview with Vanessa Feltz to decide that this was, indeed, a crisis and announce an inquiry into antisemitism (and other forms of racism) within the Labour Party. During this time, the few people close to the leadership to retain good relations with the Jewish community took soundings on the best course of action. While Mr Corbyn's staffers hunkered down behind closed doors, one of Mr McDonnell's most trusted advisers floated the idea of an inquiry to demonstrate the party was not in denial about its Jewish problem.

Last Thursday evening I was told that Mr McDonnell was in favour of an inquiry, although there was still resistance from some in Mr Corbyn's office. The only difficulty was finding someone who would be trusted by all sides. I suggested Shami Chakrabarti as I remembered from an interview with the JC that she was tough on antisemitism disguised as anti-Zionism. I passed her number on to my contact on Mr McDonnell's team and I know it was given to Seb Corbyn, who was working hard to get the inquiry off the ground.

I know there is a considerable degree of skepticism about the inquiry, particularly as there is a view that Labour's Jewish problem starts at the top, but I happen to believe Shami Chakrabarti is an honest broker, whose reputation has too much to lose from a whitewash.

I take some satisfaction from my small contribution, and I sincerely hope that the involvement of the former JC Political Editor in the choice of inquiry chair will not lead to the inevitable slurs. This is not a Zionist conspiracy; it is the right thing to do.