The Labour Party has been thrown into uproar by a leaked report, prepared by party officials in the final days of Jeremy Corbyn’s leadership, which makes a series of headline-grabbing claims. Keir Starmer and Angela Rayner, the party’s new leader and deputy, have announced an independent inquiry into both the report’s contents and its leaking, which has released into the public domain the names of multiple people who made complaints about anti-Semitism in Labour.

The report was first leaked to Sky News but has since found its way to journalists at several other publications, including the New Statesman. Its central case is that complaints about anti-Semitism within Labour were poorly handled from September 2015 to April 2018 because the party’s machinery was in the hands of committed Corbynsceptics, whose first aim was to wreck Jeremy Corbyn’s leadership. The report suggests that from April 2018 onwards – when Corbyn’s control of headquarters was completed with the installation of Jennie Formby as Labour’s general secretary – the party handled complaints about anti-Semitism with the same level of effectiveness as any others. As a secondary consequence of that argument, the report alleges that senior staffers at Labour headquarters deliberately undermined the party’s 2017 election effort.

In both cases, the report’s summary writes a cheque that its findings cannot cash. It’s clear that when Jeremy Corbyn became the leader of the Labour Party, he faced considerable internal opposition, not just within the Parliamentary Labour Party, but within the party machinery. As James Schneider, one of Corbyn’s aides, recently put it: Corbyn had to “struggle in and against the party” as well as against his external opponents.

As I wrote throughout the half-decade of Corbyn’s leadership, the top team at Labour headquarters was from 2015 to 2017 dominated by staffers who would have preferred Yvette Cooper to win the 2015 leadership election, and for Ed Balls or David Miliband to have won the 2010 contest. Before Corbyn, the politics of Labour’s headquarters were therefore most accurately described as “right-Brownite”. And as I reported back in 2015, party staffers had nicknamed the effort to police who could vote in the leadership election “Operation Ice Pick”, after the weapon used to murder Leon Trotsky in 1940. Many in party headquarters believed that Corbynism was the result of infiltration, a disease to be purged from the bloodstream.

In the 2017 election, Labour fought a defensive campaign – and given the closesness of several Conservative holds, in seats as varied as Hastings and Bolton West, a more ambitious campaign might well have been the difference between a Conservative minority government and a Labour minority one. Labour spent money and activist time on trying to prevent a Liberal Democrat surge (which, in the end, never came to be) in places such as Streatham, south London, and seeing off a Conservative challenge in seats it held such as Gedling and Ilford North, while narrowly failing to win from the Tories the likes of Ruislip and Uxbridge, Chingford and Wood Green, Southampton Itchen or Pudsey.

Some in Corbyn’s inner circle saw this as the result of simple pessimism, based on faulty polls. The party’s own pollster, BMG Research, had failed to pick up on its surge. But others believed that this was the result of deliberate wrecking tactics on the part of HQ.

This report does not conclusively prove that argument. It collects what are alleged to be multiple and repeated examples of communication between senior staff at Labour HQ showing bitter and in some cases deeply personal opposition to Corbyn, his staff and his close parliamentary allies. But it doesn’t successfully draw a conclusive line between that behaviour and a deliberate attempt to sabotage Labour either in 2017 or in the battle against anti-Semitism.

Whether such a link existed will form one of the three pillars of the independent inquiry that Starmer and Rayner have set up. Another pillar will concern the report's leaking, while the third will look at the circumstances in which the report was commissioned.

That last pillar is more important than it sounds. The report also fails to prove its case on the 2018-20 period – the point at which Corbyn had control over the machinery, and his preferred general secretary in place. It was during this period that Peter Willsman was allowed to remain on the Labour National Executive Committee for more than six months after the release of a recording of an NEC meeting in which he said that claims of Labour anti-Semitism were the creation of “Trump fanatics” in the British Jewish community.

The very existence of yet another Labour-run report into this issue is a pretty damning piece of evidence that the party’s hierarchy had not got to grips with the issue. The central political demand of the Jewish Labour Movement and most of the Jewish community’s communal organisations has been for an independent process. Labour’s institutional problems did not begin with Jeremy Corbyn and they will not end simply because he is no longer the party's leader. But a vital prerequisite of tackling the problem is that Labour stops trying to mark its own homework. This topic ought to have been handled in the same way as the party's sexual harassment claims, which Karon Monaghan, the widely respected equalities lawyer, was brought in to investigate, rather than the matter being dealt with internally. That this now widely leaked report includes the unredacted personal details of people who complained about anti-Semitism makes its existence worse still.

This attests to the scale of the task before Starmer and Rayner – who, whether the report is true or false, have inherited an organisation badly in need of a change of culture and approach that goes well beyond the failure to tackle anti-Semitism in its ranks.