The public service broadcaster engaged in a "significant breach" of media regulations by failing to disclose that the voice of a film about the Gaza conflict was the offspring of a Hamas official, according to regulatory body Ofcom.
An inquiry by Ofcom into the programme Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The head of the BBC had earlier expressed regret, saying there had been "a significant failing in relation to factual correctness".
The regulator has instructed the broadcaster to transmit a peak-time declaration about its decisions.
"Since this amounts to a significant violation of our code, we are ordering the BBC to transmit a message of our determinations against it on the BBC's second channel at nine o'clock in the evening, with a timing to be finalised," the statement read.
'Potential to Damage Trust'
The watchdog's report said: "Our probe determined that the documentary's omission to reveal that the voice's parent occupied a position in the Hamas-run authority was significantly deceptive.
"Consequently that the audience did not have essential details which may have been extremely pertinent to their judgment of the voice and the information he shared.
"Confidence is at the center of the relationship between a media organization and its public, particularly for a public service broadcaster such as the public broadcaster.
"This failing had the risk to erode the very considerable amounts of confidence that viewers would have placed in a documentary produced by the BBC about the Israel-Gaza war."
The film was withdrawn from the BBC's streaming service in the month of February after the narrator's familial connections emerged, and in July an broadcaster's internal assessment concluded it infringed the organization's journalistic standards on truthfulness.
A BBC spokesperson stated: "The authority's determination is in line with the findings of the internal assessment, that there was a major oversight in the programme in relation to the corporation's content standards on truthfulness, which reflects regulation 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we agree with the regulator's ruling in complete. We will comply with the sanction as soon as the schedule and wording are finalised."
