The public service broadcaster was found to have committed a "significant breach" of media regulations by omitting to mention that the presenter of a programme about Gaza was the child of a Hamas administrator, according to regulatory body Ofcom.
An probe by the media regulator into Gaza: How to Survive a Warzone has concluded that the programme was "materially misleading".
The head of the BBC had previously apologised, noting there had been "a major oversight in relation to factual correctness".
The regulator has directed the broadcaster to broadcast a prime-time declaration about its conclusions.
"As this represents a major infringement of our rules, we are directing the BBC to transmit a announcement of our findings against it on the BBC's second channel at nine o'clock in the evening, with a schedule to be determined," the statement read.
'Risk to Undermine Confidence'
The authority's announcement said: "The inquiry we conducted concluded that the film's failure to disclose that the voice's father occupied a position in the Hamas-controlled authority was materially misleading.
"This implied that the viewers did not have essential details which may have been highly relevant to their assessment of the presenter and the content he presented.
"Credibility is at the heart of the connection between a media organization and its audience, notably for a public service broadcaster such as the BBC.
"This error had the risk to undermine the exceptionally strong amounts of credibility that viewers would have put in a BBC factual programme about the Gaza conflict."
The film was withdrawn from the BBC's streaming service in February after the narrator's familial connections were revealed, and in this past July an internal BBC review concluded it violated the corporation's editorial guidelines on truthfulness.
A corporation official commented: "The Ofcom ruling is in line with the results of the internal assessment, that there was a significant failing in the documentary in relation to the BBC's Editorial Guidelines on truthfulness, which reflects Rule 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we comply with the authority's determination in full. We will follow the sanction as soon as the schedule and wording are finalised."
