The BBC committed a "major breach" of industry standards by omitting to mention that the narrator of a programme about the Gaza situation was the offspring of a Hamas representative, 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 film was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a significant failing in relation to truthfulness".
The regulator has directed the BBC to transmit a peak-time declaration about its decisions.
"Since this amounts to a major infringement of our rules, we are directing the BBC to air a announcement of our conclusions against it on BBC Two at nine o'clock in the evening, with a date to be confirmed," the statement read.
'Potential to Undermine Trust'
The watchdog's report stated: "Our investigation found that the documentary's failure to disclose that the presenter's male guardian served in a position in the Hamas-administered government was substantially inaccurate.
"Consequently that the public did not have essential details which may have been very significant to their assessment of the voice and the information he provided.
"Confidence is at the core of the relationship between a television network and its audience, especially for a public service broadcaster such as the British Broadcasting Corporation.
"This failing had the possibility to undermine the very considerable amounts of credibility that the public would have invested in a documentary produced by the BBC about the Gaza conflict."
The film was removed from the BBC's streaming service in the month of February after the narrator's familial connections were revealed, and in July an broadcaster's internal assessment found it violated the broadcaster's editorial guidelines on factual correctness.
A BBC spokesperson stated: "The regulator's decision is in line with the results of the corporation's inquiry, that there was a serious error in the film in relation to the BBC's Editorial Guidelines on truthfulness, which aligns with Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we accept Ofcom's decision in complete. We will adhere to the directive as soon as the timing and wording are finalised."
