The BBC committed a "significant breach" of industry standards by omitting to mention that the narrator of a programme about the Gaza conflict was the child of a Hamas official, as determined by UK media regulator Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has concluded that the documentary was "materially misleading".
The head of the BBC had previously apologised, saying there had been "a major oversight in relation to factual correctness".
The authority has instructed the broadcaster to air a peak-time statement about its findings.
"As this represents a significant violation of our regulations, we are instructing the broadcaster to air a announcement of our findings against it on BBC2 at nine o'clock in the evening, with a date to be finalised," it said.
'Possibility to Erode Trust'
The authority's statement stated: "The inquiry we conducted found that the documentary's omission to reveal that the presenter's male guardian occupied a position in the Hamas-administered authority was significantly deceptive.
"It meant that the public did not have critical information which may have been very significant to their judgment of the voice and the content he provided.
"Confidence is at the core of the connection between a broadcaster and its viewers, particularly for a public service broadcaster such as the public broadcaster.
"This failing had the possibility to damage the exceptionally strong amounts of credibility that audiences would have invested in a BBC factual programme about the Israel-Gaza war."
The documentary was pulled from the BBC's streaming service in February after the narrator's personal associations emerged, and in July an internal BBC review determined it infringed the organization's content policies on accuracy.
A corporation official stated: "The Ofcom ruling is in line with the results of the corporation's inquiry, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on factual correctness, which aligns with clause 2.2 of the regulator's media standards.
"We issued an apology for this and we agree with the authority's determination in its entirety. We will comply with the sanction as soon as the timing and wording are confirmed."
