The German judge overseeing Fifa’s investigation into the controversial bidding process for the 2018 and 2022 World Cups has insisted that the report cannot be published in full for legal reasons, but promised an overview of the main findings by the middle of next month.

Hans-Joachim Eckert, the chair of the adjudicatory arm of Fifa's ethics committee, received the 360-page report and 200,000 pages of supporting documents from Michael Garcia, the former US attorney for the southern district of New York who is head of the investigatory arm, last month.

Ever since, a battle has raged over whether and when it will be published. Garcia and several members of the Fifa executive committee have called for it to be published in full, with names redacted to protect whistleblowers, in order to help restore Fifa's battered credibility.

Eckert has now moved to clarify the situation in an interview posted on Fifa’s website, promising to deliver a statement by mid-November at the latest but again ruling out full publication of Garcia’s report.

“The statement will contain an overview of the investigation report, a summary of the main findings, conclusions and recommendations of the report, as well as a brief evaluation of the same,” he said.

The German judge, appointed as part of Fifa’s reform process as it tried to come to terms with the fallout from a string of corruption allegations, said that because those interviewed had been promised confidentiality it would be all but impossible to publish the report in full.

“Publishing the report in full would actually put the Fifa ethics committee and Fifa itself in a very difficult situation legally,” he said. “What is more, we have to respect the personal rights of the people mentioned in the report, which in the case of full publication of the report would in all likelihood not be possible.”

Garcia reiterated his call for more transparency in a speech to US lawyers in London earlier this week but Eckert insisted there was no rift between them. He said: “Michael Garcia has never said that the report should be 100 per cent published. He merely said that the ‘appropriate’ publication of his report should be authorised. The deputy chairman of the adjudicatory chamber and I now have the task of drawing up this appropriate form for publication.

“Part of my current examination involves deciding what form this appropriate publication should take, whether this means issuing a statement regarding the investigation report or whether certain parts of the investigation report will be published while maintaining anonymity, or indeed a combination of these possibilities. This decision is exclusively a matter for the adjudicatory chamber – neither the investigatory chamber nor the Fifa executive committee can decide. The main requirement is that personal rights must not be damaged.”

Eckert, who has been under pressure to clarify his position, said in September that his own judgment based on Garcia’s investigation, likely to be delivered early next year, would not go down well with many at Fifa. “Many won’t like what I am going to tell them,” he warned.

He also attempted to deal with claims that Garcia was compromised because he was an American citizen investigating a bidding race in which the US played an integral part. The US would be in pole position to host the 2022 tournament if it was stripped from Qatar.

"It must be pointed out that the main report has been produced not by Michael Garcia alone, but also by the deputy chairman of the investigatory chamber of the Fifa ethics committee, Cornel Borbély. In fact, the report into Russia and the USA was produced solely by Cornel Borbély," said Eckert.

“This is because Michael Garcia was unable to take part in some parts of the investigation due to the possibility of conflicts of interest, for example in the case of the American bid (as he is a US citizen).”

Controversy has surrounded the controversial and chaotic decision to award the 2018 World Cup to Russia and the 2022 tournament to Qatar ever since the vote in December 2010. Mohamed Bin Hammam, the disgraced former president of the Asian Football Confederation, has been linked to paying a string of bribes during the Qatari's failed bid to become Fifa president, with some linking his activities to the concurrent Qatar 2022 bid. The failed bidders, including the US, Australian and England, also come under scrutiny.

Eckert has said that only four people have access to Garcia's report, but other sources claim to have seen parts of it. It is said to focus on breaches of the ethics code by several individuals but Eckert and the Fifa president Sepp Blatter have said only Fifa's executive committee would have the power to strip either Russia or Qatar of the World Cup. Garcia travelled to all the bidding countries, except for Russia where he is barred from entry due to the country's continuing dispute with the US over sanctions, to gather evidence over an 18-month period.

In his speech in London, Garcia called for a culture change among Fifa’s leadership and called for an end to the prevailing veil of secrecy at the Zurich-based governing body. “The investigation and adjudication process operates in most parts unseen and unheard,” he said. “That’s a kind of system which might be appropriate for an intelligence agency but not for an ethics compliance process in an international sports institution that serves the public and is the subject of intense public scrutiny.”