The public service broadcaster engaged in a "serious breach" of broadcasting rules by not revealing that the narrator of a film about the Gaza situation was the offspring of a Hamas representative, as determined by regulatory body Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has determined that the documentary was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a serious error in relation to factual correctness".
The authority has instructed the corporation to broadcast a prime-time announcement about its decisions.
"As this represents a major infringement of our code, we are directing the corporation to transmit a announcement of our findings against it on BBC Two at nine o'clock in the evening, with a timing to be confirmed," it said.
'Possibility to Undermine Credibility'
The regulator's report said: "The inquiry we conducted found that the film's failure to disclose that the presenter's parent held a role in the Hamas-administered administration was significantly deceptive.
"Consequently that the viewers did not have critical information which may have been very significant to their evaluation of the presenter and the content he shared.
"Trust is at the heart of the connection between a television network and its viewers, especially for a state-funded media outlet such as the BBC.
"This oversight had the risk to erode the significantly high degrees of trust that the public would have placed in a factual film from the broadcaster about the Gaza conflict."
The documentary was withdrawn from iPlayer in last February after the boy's family links came to light, and in July an internal BBC review determined it breached the organization's journalistic standards on accuracy.
A BBC spokesperson said: "The authority's determination is in accordance with the results of the internal assessment, that there was a major oversight in the programme in relation to the corporation's content standards on factual correctness, which aligns with regulation 2.2 of the regulator's media standards.
"We expressed regret for this and we agree with the authority's determination in complete. We will follow the penalty as soon as the schedule and wording are finalised."
