The BBC engaged in a "major breach" of media regulations by omitting to mention that the narrator of a programme about the Gaza conflict was the child of a Hamas representative, as ruled by UK media regulator Ofcom.
An investigation by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the programme was "materially misleading".
The BBC's director general had previously apologised, noting there had been "a major oversight in relation to factual correctness".
The authority has directed the BBC to transmit a peak-time announcement about its decisions.
"Since this amounts to a major infringement of our regulations, we are instructing the BBC to air a statement of our determinations against it on BBC2 at 21:00, with a timing to be confirmed," the regulator stated.
'Risk to Damage Trust'
The watchdog's report said: "The inquiry we conducted concluded that the documentary's failure to disclose that the presenter's father held a post in the Hamas-administered government was materially misleading.
"This implied that the audience did not have critical information which may have been extremely pertinent to their evaluation of the voice and the details he presented.
"Credibility is at the heart of the bond between a broadcaster and its viewers, especially for a state-funded media outlet such as the public broadcaster.
"This failing had the potential to erode the exceptionally strong levels of confidence that the public would have invested in a BBC factual programme about the conflict in Gaza."
The film was withdrawn from the BBC's streaming service in February after the narrator's family links emerged, and in this past July an corporation's own inquiry determined it breached the corporation's journalistic standards on accuracy.
A representative for the broadcaster stated: "The regulator's decision is in agreement with the findings of the internal assessment, that there was a major oversight in the film in relation to the broadcaster's journalistic policies on factual correctness, which reflects clause 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we accept the authority's determination in its entirety. We will follow the sanction as soon as the schedule and wording are finalised."
