The public service broadcaster engaged in a "major breach" of industry standards by omitting to mention that the voice of a documentary about Gaza was the son of a Hamas representative, as ruled by British broadcasting authority Ofcom.
An probe by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the film was "substantially inaccurate".
The head of the BBC had previously apologised, stating there had been "a major oversight in relation to accuracy".
The regulator has directed the BBC to transmit a peak-time announcement about its conclusions.
"Since this amounts to a major infringement of our rules, we are instructing the broadcaster to air a message of our findings against it on BBC Two at 9pm, with a date to be determined," the statement read.
'Potential to Undermine Trust'
The authority's statement said: "Our investigation concluded that the documentary's failure to disclose that the voice's male guardian held a role in the Hamas-run government was materially misleading.
"It meant that the audience did not have critical information which may have been highly relevant to their assessment of the voice and the details he provided.
"Trust is at the heart 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 erode the significantly high levels of confidence that audiences would have put in a documentary produced by the BBC about the conflict in Gaza."
The documentary was removed from the online platform in last February after the boy's familial connections emerged, and in the month of July an corporation's own inquiry determined it violated the broadcaster's journalistic standards on truthfulness.
A BBC spokesperson commented: "The authority's determination is in line with the findings of the internal assessment, that there was a serious error in the film in relation to the broadcaster's journalistic policies on factual correctness, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we agree with the regulator's ruling in full. We will adhere to the penalty as soon as the timing and wording are determined."
