The public service broadcaster committed a "serious breach" of media regulations by omitting to mention that the presenter of a programme about the Gaza situation was the child of a Hamas representative, according to UK media regulator Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has concluded that the programme was "materially misleading".
The BBC's director general had previously apologised, saying there had been "a serious error in relation to accuracy".
The regulator has instructed the BBC to transmit a prime-time declaration about its findings.
"Given this constitutes a serious breach of our rules, we are instructing the corporation to transmit a statement of our findings against it on BBC Two at nine o'clock in the evening, with a timing to be finalised," the regulator stated.
'Potential to Erode Confidence'
The watchdog's announcement stated: "Our probe determined that the programme's failure to disclose that the narrator's male guardian served in a position in the Hamas-controlled government was significantly deceptive.
"Consequently that the audience did not have critical information which may have been extremely pertinent to their evaluation of the narrator and the information he provided.
"Credibility is at the core of the connection between a broadcaster and its public, notably for a national broadcasting corporation such as the British Broadcasting Corporation.
"This error had the possibility to erode the exceptionally strong levels of confidence that viewers would have invested in a documentary produced by the BBC about the conflict in Gaza."
The documentary was pulled from the online platform in the month of February after the narrator's personal associations were revealed, and in this past July an internal BBC review determined it violated the organization's journalistic standards on accuracy.
A corporation official stated: "The regulator's decision is in line with the conclusions of Peter Johnston's review, that there was a major oversight in the programme in relation to the broadcaster's journalistic policies on accuracy, which corresponds to regulation 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we accept the regulator's ruling in its entirety. We will adhere to the penalty as soon as the timing and wording are confirmed."
