The public service broadcaster engaged in a "major breach" of media regulations by omitting to mention that the voice of a programme about the Gaza situation was the son of a Hamas representative, as ruled by regulatory body Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The BBC's director general had already issued an apology, noting there had been "a serious error in relation to truthfulness".
The authority has instructed the corporation to transmit a prime-time declaration about its conclusions.
"Given this constitutes a significant violation of our regulations, we are ordering the BBC to transmit a announcement of our determinations against it on BBC Two at nine o'clock in the evening, with a date to be determined," the regulator stated.
'Potential to Damage Confidence'
The authority's announcement stated: "The inquiry we conducted determined that the film's omission to reveal that the narrator's father occupied a role in the Hamas-run government was significantly deceptive.
"It meant that the viewers did not have vital facts which may have been highly relevant to their judgment of the voice and the details he presented.
"Credibility is at the center of the relationship between a television network and its audience, particularly for a national broadcasting corporation such as the British Broadcasting Corporation.
"This error had the potential to damage the very considerable levels of trust that the public would have invested in a documentary produced by the BBC about the conflict in Gaza."
The programme was pulled from the online platform in February after the presenter's personal associations came to light, and in July an corporation's own inquiry found it violated the broadcaster's journalistic standards on factual correctness.
A corporation official stated: "The authority's determination is in agreement with the results of Peter Johnston's review, that there was a serious error in the programme in relation to the BBC's Editorial Guidelines on truthfulness, which reflects clause 2.2 of the regulator's media standards.
"We expressed regret for this and we accept the authority's determination in complete. We will adhere to the penalty as soon as the date and language are finalised."
