The BBC engaged in a "major breach" of industry standards by omitting to mention that the narrator of a programme about the Gaza situation was the offspring of a Hamas representative, according to regulatory body Ofcom.
An investigation by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the documentary was "materially misleading".
The BBC's director general had already issued an apology, stating there had been "a major oversight in relation to accuracy".
The regulator has directed the broadcaster to transmit a evening announcement about its findings.
"Since this amounts to a significant violation of our code, we are directing the corporation to transmit a statement of our determinations against it on BBC2 at nine o'clock in the evening, with a schedule to be determined," the statement read.
'Possibility to Undermine Credibility'
The authority's report stated: "The inquiry we conducted determined that the documentary's failure to disclose that the presenter's father served in a post in the Hamas-controlled administration was substantially inaccurate.
"Consequently that the public did not have essential details which may have been very significant to their evaluation of the presenter and the information he shared.
"Credibility is at the core of the relationship between a media organization and its viewers, especially for a national broadcasting corporation such as the BBC.
"This oversight had the potential to damage the very considerable degrees of credibility that viewers would have invested in a documentary produced by the BBC about the conflict in Gaza."
The film was pulled from iPlayer in the month of February after the presenter's familial connections came to light, and in the month of July an corporation's own inquiry found it violated the organization's content policies on factual correctness.
A corporation official stated: "The authority's determination is in accordance with the findings of the internal assessment, that there was a serious error in the film in relation to the BBC's Editorial Guidelines on truthfulness, which corresponds to Rule 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept Ofcom's decision in its entirety. We will adhere to the directive as soon as the date and wording are finalised."
