The public service broadcaster engaged in a "significant breach" of media regulations by not revealing that the narrator of a programme about the Gaza conflict was the child of a Hamas official, as ruled by UK media regulator Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has found that the documentary was "significantly deceptive".
The BBC's director general had earlier expressed regret, stating there had been "a serious error in relation to accuracy".
The authority has instructed the broadcaster to broadcast a evening declaration about its conclusions.
"As this represents a significant violation of our code, we are instructing the broadcaster to air a statement of our findings against it on BBC Two at 21:00, with a schedule to be determined," it said.
'Potential to Erode Credibility'
The authority's announcement said: "The inquiry we conducted determined that the programme's omission to reveal that the presenter's father occupied a post 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 judgment of the presenter and the content he presented.
"Trust is at the heart of the bond between a media organization and its audience, especially for a public service broadcaster such as the BBC.
"This error had the possibility to erode the exceptionally strong amounts of confidence that viewers would have invested in a BBC factual programme about the Israel-Gaza war."
The programme was pulled from the online platform in the month of February after the narrator's familial connections came to light, and in this past July an broadcaster's internal assessment concluded it breached the organization's editorial guidelines on factual correctness.
A corporation official stated: "The authority's determination is in agreement with the conclusions of the internal assessment, that there was a major oversight in the documentary in relation to the corporation's content standards on truthfulness, which corresponds to clause 2.2 of the regulator's media standards.
"We have apologised for this and we agree with Ofcom's decision in complete. We will follow the sanction as soon as the timing and language are finalised."
