The public service broadcaster was found to have committed a "significant breach" of media regulations by failing to disclose that the presenter of a programme about Gaza was the son of a Hamas official, according to British broadcasting authority Ofcom.
An inquiry by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has determined that the film was "substantially inaccurate".
The BBC's director general had earlier expressed regret, noting there had been "a significant failing in relation to factual correctness".
Ofcom has ordered the broadcaster to air a peak-time announcement about its conclusions.
"Given this constitutes a major infringement of our regulations, we are ordering the broadcaster to broadcast a message of our determinations against it on BBC Two at nine o'clock in the evening, with a schedule to be confirmed," it said.
'Possibility to Erode Confidence'
The watchdog's report said: "Our probe found that the documentary's lack of disclosure that the voice's father served in a post in the Hamas-administered administration was substantially inaccurate.
"Consequently that the public did not have essential details which may have been very significant to their assessment of the narrator and the information he presented.
"Credibility is at the heart of the relationship between a television network and its audience, particularly for a national broadcasting corporation such as the BBC.
"This error had the potential to damage the exceptionally strong levels of confidence that viewers would have invested in a documentary produced by the BBC about the conflict in Gaza."
The programme was withdrawn from the online platform in February after the narrator's personal associations emerged, and in July an internal BBC review determined it breached the broadcaster's journalistic standards on truthfulness.
A corporation official stated: "The regulator's decision is in line with the results of Peter Johnston's review, that there was a significant failing in the film in relation to the BBC's Editorial Guidelines on accuracy, which corresponds to clause 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with the authority's determination in full. We will comply with the sanction as soon as the date and wording are confirmed."
