The public service broadcaster committed a "major breach" of industry standards by failing to disclose that the voice of a programme about the Gaza conflict was the child of a Hamas official, as ruled by regulatory body Ofcom.
An inquiry by the media regulator into the programme Gaza: How to Survive a Warzone has concluded that the film was "substantially inaccurate".
The BBC's director general had previously apologised, stating there had been "a serious error in relation to truthfulness".
The regulator has instructed the corporation to transmit a evening statement about its findings.
"Given this constitutes a major infringement of our regulations, we are ordering the broadcaster to air a message of our determinations against it on the BBC's second channel at 9pm, with a schedule to be determined," the regulator stated.
'Possibility to Undermine Confidence'
The regulator's statement said: "Our probe found that the documentary's omission to reveal that the narrator's parent occupied a post in the Hamas-administered authority was materially misleading.
"This implied that the viewers did not have critical information which may have been extremely pertinent to their judgment of the narrator and the details he provided.
"Credibility is at the center of the bond between a broadcaster and its public, particularly for a state-funded media outlet such as the British Broadcasting Corporation.
"This error had the possibility to undermine the significantly high levels of credibility that the public would have invested in a factual film from the broadcaster about the conflict in Gaza."
The documentary was removed from the BBC's streaming service in last February after the narrator's family links came to light, and in July an corporation's own inquiry concluded it breached the corporation's journalistic standards on truthfulness.
A BBC spokesperson stated: "The authority's determination is in line with the conclusions of the corporation's inquiry, that there was a major oversight in the documentary in relation to the corporation's content standards on accuracy, which aligns with regulation 2.2 of the regulator's media standards.
"We issued an apology for this and we accept Ofcom's decision in its entirety. We will adhere to the sanction as soon as the schedule and wording are confirmed."
