The Pollard Review, which is examining a shelved Newsnight report into Jimmy Savile’s alleged abuse, is to take about a month longer than expected.
The need to conduct further interviews, examine documents and prepare the report will mean it is not expected to be delivered until mid-December.
Former Sky News executive Nick Pollard, who is chairing the review, said it was making “good progress”.
It is looking into a planned news investigation into Savile late last year, which was dropped by the BBC2 programme. The axing of the proposed probe set in motion a chain of events which led to BBC director-general George Entwistle resigning from his post after just 54 days.
Yesterday the BBC fast-tracked a replacement as head of the corporation when Royal Opera House chief executive Tony Hall was appointed as the new DG, taking over in March.
Mr Pollard was commissioned to lead the review on October 16 and his report had been expected to be delivered by this month.
He said yesterday: “While good progress is being made, it has become clear that it will not be possible for the review to report, as originally planned, during the second half of November.
“Taking into account the need for a thorough and fair process, the further interviews planned, the need to consider additional documents and the time required for report preparation, I have informed the BBC that I now expect to provide my report to the BBC by mid-December.”
The review has already looked at “many thousands of documents” and has received 40 written submissions. So far 12 interviews have been conducted with more planned.”
Mr Pollard said the level of co-operation had been good and his team were grateful to the BBC and witnesses.
The Newsnight programme sparked a crisis at the BBC which erupted just days after Mr Entwistle took office.
There had been suggestions that the report was pulled because the corporation was planning TV tributes to the late presenter although these were denied by the corporation. The Pollard Review is looking into the decision-making process, while another inquiry is being led by Dame Janet Smith which is examining the culture and practices of the BBC during the years in which Savile worked there.