Within hours of Ian Austin announcing that he was resigning as a Labour MP because of what he called a “culture of extremism, antisemitism and intolerance”, news broke of Labour’s latest initiative to eradicate a problem that has bedevilled Jeremy Corbyn throughout his leadership.

Austin, the adopted son of Jewish parents, made his announcement on 22 February, only days after eight other Labour MPs had resigned the whip to form a new independent group. Labour was at risk of imploding. All of them cited antisemitism in Labour’s ranks, and the party’s persistent failure to root it out, as one of their main reasons for going. Something had to be done to stem the tide of desertions.

Action to deal with racism and antisemitism has been pledged so often by Labour’s high command in recent years that it has been difficult to keep track. There was a report into the issue by Shami Chakrabarti in 2016 that made a string of recommendations for reform. Internal structures for investigating cases have been reorganised repeatedly. Last year the party appointed a barrister, Gordon Nardell QC, to offer legal advice. With each new crisis, Corbyn is first lambasted for inaction and then he calls for zero-tolerance.

But – as proved by events of the past 10 days, culminating in the suspension of the MP and Corbyn ally Chris Williamson for saying Labour had been “too apologetic” about antisemitism and had been “demonised” as a racist party – the issue never goes away. On the contrary, it increasingly divides and poisons relations between elements of the Corbyn-supporting left, and those less supportive of the leader’s politics.

The latest big idea from Labour’s high command to address the problem – made public on the day of Austin’s leaving – was to appoint the former lord chancellor Charlie Falconer as an independent reviewer of complaints. But, as ever with Labour and antisemitism, it is not that straightforward.

On Saturday – after the party general secretary Jennie Formby had, in a furious email, told the deputy leader Tom Watson to keep his hands off antisemitism issues, because Falconer was now on the case – Falconer told the Observer that he had, in fact, not yet reached agreement with the party over what his job would be and how the whole thing would work.

Formby was, it appeared, jumping the gun in her war with Watson. “In principle I want to do it, but the terms of reference and resources that will be available have to be agreed before I can take on the role,” he said. Nothing was nailed on.

One way of looking at Labour’s antisemitism crisis, which has created a backlog of hundreds of cases in the complaints unit, is to view it all as administrative incompetence. That may explain why Formby suggested Falconer’s role was agreed in her tirade against Watson. Wires got crossed. It may also explain why an investigation by the national executive committee into allegations of antisemitism against Ken Livingstone, the former London mayor, promised by Corbyn in April 2017, had not even begun by the following February. Whatever the reason, the party has never appeared fully in control even of many of the most serious cases it has had to deal with.

An inquiry was announced into allegations of antisemitism against Ken Livingstone. Photograph: Roger Askew/Rex/Shutterstock

The other interpretation that Austin and other defectors would subscribe to is that there is a deliberate unwillingness in Corbyn-supporting circles to clamp down as fast and hard as they should. This was fuelled last year by the prolonged argument over Corbyn’s reluctance to adopt the full internationally accepted definition of antisemitism and all its examples. The issue caused what could possibly be an irreparable rift between Labour and the Jewish community.

The new evidence that we publish today, showing that senior officials opposed the suspension of some members accused of antisemitism, will add to the concerns of those who believe there is a reluctance in some quarters to act. The question raised is not whether the right decision was reached, but over transparency and the process at the time.

Emails seen by the Observer reveal some cases between March and May last year in which an official acting on behalf of Formby opposed a recommendation from investigators to impose some suspensions, preferring less serious action. In one case in March, Andrew Murray, an adviser to Jeremy Corbyn’s office, also opposed a recommendation in favour of less serious action. It was in relation to a member who had allegedly defended an antisemitic mural.

In another case, the official acting on behalf of Formby opposed the suspension of a member who had posted a picture of an alien with the Star of David printed on it, smothering the face of the Statue of Liberty. The official instead suggested handing the member a “reminder of conduct”.

Labour sources said the number of cases where recommendations had been opposed was small and a highly selective sample, while final decisions lay with Labour investigators. They also said Formby had since overhauled the complaints procedure to cut out the leader’s office and the general secretary’s office.

Murray said he had only disagreed with the recommendation he had received in one case.

The problem for Labour is not confined to Westminster. The divisions are spreading to constituency parties. Several passed motions last week supporting Williamson, and backing his view that the party has been too apologetic about antisemitism just as it tries to clear out the cancer.

Last week the shadow home secretary, Diane Abbott, watched as members of the her north London party branch passed a motion rejecting the claim that Labour is “institutionally antisemitic”. The south London party branch of Chuka Umunna, one of the eight who formed the Independent Group, said the suggestions of institutional antisemitism amounted to slander. In Sheffield Hallam, where Williamson made the remarks, activists voted to oppose his suspension by 40 to one. “This really has the potential to destroy us,” was the view of one senior official involved in investigating cases of antisemitism.