Jeremy Corbyn has lost a legal fight to force Labour to hand over documents before a possible high court challenge against his suspension from the parliamentary party. The former Labour leader’s lawyers believed the documents would help him show that an agreement to fully readmit him to the party following his suspension for downplaying antisemitism under his leadership had been reneged upon. Labour has denied in court that any such deal existed. In a ruling on Wednesday, the judge Lisa Sullivan dismissed Corbyn’s claim, saying he already had sufficient information upon which to decide whether or not to bring a case. During a hearing last week the Islington North MP’s lawyers accused his successor, Keir Starmer, of “inflammatory and disingenuous” attacks. Corbyn believes his suspension was handled unfairly and was the object of political interference. He was suspended in October after he rejected some of the damning findings of an Equality and Human Rights Commission report on Labour antisemitism, saying: “One antisemite is one too many, but the scale of the problem was also dramatically overstated for political reasons by our opponents inside and outside the party, as well as by much of the media.” The refusal to acknowledge the scale of the problem under his leadership caused a rift with Starmer, who felt his predecessor had undermined work to restore trust and confidence in Labour’s ability to tackle antisemitism. Corbyn was readmitted to the party by the national executive committee in November but Starmer ordered that the Labour whip be withheld until he apologised, which Corbyn has not done, effectively suspending him from the parliamentary party. At a hearing this month, Corbyn’s barrister Christopher Jacobs said the suspension was unlawful and in breach of contract, claiming that the MP needed “pre-action disclosure” before an “anticipated claim” against Labour. But Sullivan ruled: “Corbyn has sufficient material to make a decision on the merits of his case.” It is understood Corbyn expects to launch his main legal challenge soon, though court backlogs could mean it will be some time before the case is heard. The Guardian understands he is hoping to reach a compromise over his suspension in negotiations with Labour’s chief whip, Nick Brown. Corbyn’s initial suspension was for three months and is to be reviewed in February, though it remains conditional on the apology demanded by Starmer. A Labour party spokesperson welcomed Wednesday’s decision, adding: “It is regrettable that the court’s time and our members’ money was spent on this matter. We look forward to drawing a line under this matter and uniting our party ahead of a vital set of elections.” It is understood the party will seek to recover its costs from Corbyn.