The British broadcaster was found to have committed a "serious breach" of broadcasting rules by not revealing that the narrator of a film about Gaza was the offspring of a Hamas representative, according to UK media regulator Ofcom.
An investigation by the broadcasting watchdog into Gaza: How to Survive a Warzone has determined that the programme was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a major oversight in relation to factual correctness".
The regulator has instructed the BBC to broadcast a evening announcement about its conclusions.
"Since this amounts to a major infringement of our rules, we are directing the BBC to air a statement of our findings against it on the BBC's second channel at 9pm, with a schedule to be confirmed," the statement read.
'Potential to Erode Credibility'
The watchdog's statement said: "The inquiry we conducted concluded that the programme's omission to reveal that the presenter's male guardian served in a post in the Hamas-run authority was materially misleading.
"Consequently that the public did not have essential details which may have been very significant to their judgment of the presenter and the information he shared.
"Trust is at the heart of the bond between a television network and its viewers, notably for a national broadcasting corporation such as the public broadcaster.
"This oversight had the possibility to undermine the significantly high levels of credibility that the public would have put in a documentary produced by the BBC about the conflict in Gaza."
The documentary was pulled from the online platform in last February after the boy's familial connections emerged, and in July an corporation's own inquiry determined it breached the broadcaster's content policies on factual correctness.
A representative for the broadcaster said: "The Ofcom ruling is in accordance with the results of the internal assessment, that there was a serious error in the film in relation to the corporation's content standards on truthfulness, which aligns with Rule 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with the regulator's ruling in complete. We will adhere to the penalty as soon as the date and wording are determined."
