The BBC engaged in a "significant breach" of media regulations by not revealing that the voice of a programme about Gaza was the child of a Hamas official, as ruled by British broadcasting authority Ofcom.
An probe by the media regulator into Gaza: How to Survive a Warzone has concluded that the film was "materially misleading".
The chief executive of the broadcaster had earlier expressed regret, saying there had been "a significant failing in relation to factual correctness".
The regulator has instructed the corporation to transmit a peak-time announcement about its decisions.
"Given this constitutes a serious breach of our regulations, we are instructing the BBC to air a message of our determinations against it on the BBC's second channel at 9pm, with a timing to be determined," it said.
'Possibility to Undermine Credibility'
The authority's report said: "Our investigation determined that the film's failure to disclose that the voice's father occupied a position in the Hamas-administered authority was significantly deceptive.
"Consequently that the audience did not have essential details which may have been extremely pertinent to their evaluation of the voice and the content he presented.
"Credibility is at the core of the connection between a television network and its viewers, particularly for a state-funded media outlet such as the British Broadcasting Corporation.
"This oversight had the possibility to damage the significantly high degrees of trust that audiences would have placed in a BBC factual programme about the Israel-Gaza war."
The film was pulled from the BBC's streaming service in February after the narrator's personal associations emerged, and in this past July an internal BBC review found it breached the organization's editorial guidelines on accuracy.
A BBC spokesperson stated: "The Ofcom ruling is in line with the results of the internal assessment, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we comply with the authority's determination in full. We will comply with the sanction as soon as the date and language are confirmed."
