The public service broadcaster engaged in a "serious breach" of broadcasting rules by failing to disclose that the voice of a programme about the Gaza situation was the son of a Hamas official, according to regulatory body Ofcom.
An inquiry by Ofcom into the programme Gaza: How to Survive a Warzone has determined that the documentary was "significantly deceptive".
The head of the BBC had already issued an apology, noting there had been "a major oversight in relation to factual correctness".
The authority has instructed the BBC to transmit a prime-time announcement about its conclusions.
"Given this constitutes a significant violation of our regulations, we are directing the broadcaster to broadcast a announcement of our findings against it on BBC Two at 9pm, with a date to be confirmed," it said.
'Potential to Damage Confidence'
The regulator's announcement stated: "Our investigation determined that the documentary's lack of disclosure that the narrator's parent served in a position in the Hamas-run administration was substantially inaccurate.
"It meant that the audience did not have vital facts which may have been very significant to their judgment of the voice and the details he presented.
"Confidence is at the core of the bond between a broadcaster and its public, notably for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the risk to damage the significantly high levels of credibility that viewers would have invested in a BBC factual programme about the conflict in Gaza."
The film was withdrawn from the online platform in the month of February after the narrator's family links came to light, and in the month of July an internal BBC review concluded it violated the organization's editorial guidelines on factual correctness.
A corporation official stated: "The authority's determination is in line with the results of the corporation's inquiry, that there was a significant failing in the film in relation to the broadcaster's journalistic policies on truthfulness, which corresponds to clause 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with Ofcom's decision in its entirety. We will comply with the penalty as soon as the timing and wording are finalised."
