The BBC committed a "serious breach" of media regulations by omitting to mention that the voice of a programme about the Gaza conflict was the offspring of a Hamas administrator, as ruled by regulatory body Ofcom.
An probe by the media regulator into the documentary titled Gaza: How to Survive a Warzone has found that the documentary was "significantly deceptive".
The head of the BBC had previously apologised, saying there had been "a major oversight in relation to truthfulness".
Ofcom has directed the broadcaster to air a peak-time declaration about its findings.
"As this represents a major infringement of our code, we are ordering the broadcaster to transmit a message of our findings against it on the BBC's second channel at nine o'clock in the evening, with a timing to be finalised," the statement read.
'Risk to Undermine Trust'
The regulator's statement stated: "The inquiry we conducted found that the film's omission to reveal that the presenter's parent occupied a position in the Hamas-run authority was materially misleading.
"Consequently that the audience did not have vital facts which may have been extremely pertinent to their assessment of the narrator and the details he presented.
"Trust is at the center of the connection between a media organization and its audience, particularly for a public service broadcaster such as the BBC.
"This error had the risk to erode the very considerable levels of credibility that audiences would have placed in a BBC factual programme about the Israel-Gaza war."
The programme was withdrawn from the BBC's streaming service in last February after the narrator's familial connections came to light, and in the month of July an broadcaster's internal assessment determined it violated the organization's editorial guidelines on accuracy.
A corporation official said: "The authority's determination is in line with the findings of the corporation's inquiry, that there was a major oversight in the documentary in relation to the broadcaster's journalistic policies on truthfulness, which reflects clause 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we agree with the authority's determination in complete. We will follow the sanction as soon as the date and wording are determined."
