The BBC was found to have committed a "significant breach" of media regulations by failing to disclose that the voice of a programme about Gaza was the offspring of a Hamas administrator, as determined by regulatory body Ofcom.
An inquiry by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the film was "substantially inaccurate".
The head of the BBC had previously apologised, saying there had been "a major oversight in relation to accuracy".
The regulator has instructed the corporation to broadcast a evening announcement about its decisions.
"Since this amounts to a significant violation of our regulations, we are instructing the corporation to broadcast a message of our determinations against it on BBC2 at 21:00, with a timing to be determined," the regulator stated.
'Risk to Undermine Trust'
The authority's statement declared: "The inquiry we conducted concluded that the documentary's omission to reveal that the presenter's parent served in a position in the Hamas-run authority was significantly deceptive.
"It meant that the viewers did not have critical information which may have been very significant to their assessment of the narrator and the content he presented.
"Credibility is at the heart of the relationship between a media organization and its audience, especially for a public service broadcaster such as the BBC.
"This error had the potential to undermine the very considerable levels of credibility that audiences would have put in a BBC factual programme about the conflict in Gaza."
The programme was withdrawn from iPlayer in the month of February after the presenter's familial connections came to light, and in this past July an broadcaster's internal assessment concluded it breached the corporation's editorial guidelines on accuracy.
A BBC spokesperson said: "The Ofcom ruling is in agreement 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 truthfulness, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we comply with the regulator's ruling in complete. We will follow the sanction as soon as the date and language are finalised."