The BBC was found to have committed a "major breach" of media regulations by omitting to mention that the presenter of a programme about Gaza was the offspring of a Hamas administrator, as ruled by regulatory body Ofcom.
An inquiry by Ofcom into the programme Gaza: How to Survive a Warzone has concluded that the documentary was "substantially inaccurate".
The chief executive of the broadcaster had already issued an apology, noting there had been "a serious error in relation to truthfulness".
Ofcom has instructed the BBC to transmit a peak-time declaration about its findings.
"Since this amounts to a serious breach of our rules, we are directing the corporation to transmit a statement of our findings against it on BBC2 at 21:00, with a schedule to be confirmed," the statement read.
'Potential to Erode Trust'
The authority's report said: "Our investigation determined that the documentary's failure to disclose that the narrator's father held a post in the Hamas-administered government was substantially inaccurate.
"This implied that the audience did not have vital facts which may have been highly relevant to their evaluation of the voice and the information he provided.
"Confidence is at the core of the connection between a media organization and its public, particularly for a public service broadcaster such as the BBC.
"This error had the potential to undermine the exceptionally strong amounts of credibility that the public would have put in a BBC factual programme about the Israel-Gaza war."
The film was pulled from iPlayer in the month of February after the narrator's family links came to light, and in July an corporation's own inquiry concluded it violated the organization's journalistic standards on truthfulness.
A corporation official commented: "The authority's determination is in agreement with the results of Peter Johnston's review, that there was a significant failing in the programme in relation to the broadcaster's journalistic policies on accuracy, which aligns with regulation 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we agree with the authority's determination in full. We will comply with the penalty as soon as the schedule and wording are determined."
