The BBC engaged in a "serious breach" of media regulations by omitting to mention that the narrator of a film about the Gaza situation was the offspring of a Hamas official, as determined by regulatory body Ofcom.
An inquiry by the media regulator into the programme Gaza: How to Survive a Warzone has found that the film was "substantially inaccurate".
The chief executive of the broadcaster had previously apologised, stating there had been "a significant failing in relation to truthfulness".
Ofcom has ordered the BBC to transmit a peak-time declaration about its decisions.
"As this represents a significant violation of our regulations, we are instructing the corporation to broadcast a message of our determinations against it on the BBC's second channel at nine o'clock in the evening, with a schedule to be confirmed," the regulator stated.
'Possibility to Erode Credibility'
The watchdog's statement stated: "Our investigation found that the programme's lack of disclosure that the voice's male guardian served in a position in the Hamas-controlled authority was materially misleading.
"This implied that the public did not have essential details which may have been highly relevant to their assessment of the voice and the content he shared.
"Trust is at the center of the bond between a television network and its audience, particularly for a public service broadcaster such as the BBC.
"This failing had the potential to damage the very considerable degrees of confidence that the public would have placed in a BBC factual programme about the conflict in Gaza."
The film was withdrawn from the BBC's streaming service in last February after the narrator's family links emerged, and in this past July an internal BBC review concluded it breached the broadcaster's journalistic standards on factual correctness.
A corporation official said: "The authority's determination is in agreement with the results of the corporation's inquiry, that there was a major oversight in the film in relation to the BBC's Editorial Guidelines on accuracy, which reflects regulation 2.2 of the regulator's media standards.
"We issued an apology for this and we agree with the regulator's ruling in complete. We will adhere to the sanction as soon as the timing and language are confirmed."
