The public service broadcaster committed a "serious breach" of media regulations by omitting to mention that the voice of a programme about the Gaza conflict was the child of a Hamas official, according to UK media regulator Ofcom.
An inquiry by the broadcasting watchdog into the documentary titled Gaza: How to Survive a Warzone has determined that the programme was "substantially inaccurate".
The BBC's director general had earlier expressed regret, saying there had been "a serious error in relation to accuracy".
The authority has directed the BBC to broadcast a peak-time announcement about its findings.
"As this represents a major infringement of our rules, we are directing the corporation to transmit a message of our conclusions against it on BBC Two at nine o'clock in the evening, with a timing to be finalised," the statement read.
'Potential to Erode Credibility'
The authority's report stated: "Our investigation found that the film's omission to reveal that the narrator's father served in a role in the Hamas-administered authority was materially misleading.
"This implied that the viewers did not have essential details which may have been highly relevant to their judgment of the narrator and the content he provided.
"Credibility is at the center of the connection between a television network and its audience, especially for a national broadcasting corporation such as the BBC.
"This oversight had the possibility to undermine the very considerable degrees of confidence that audiences would have placed in a factual film from the broadcaster about the conflict in Gaza."
The film was removed from the BBC's streaming service in February after the boy's familial connections emerged, and in this past July an corporation's own inquiry concluded it violated the broadcaster's journalistic standards on truthfulness.
A BBC spokesperson commented: "The regulator's decision is in agreement with the results of the corporation's inquiry, that there was a significant failing in the documentary in relation to the broadcaster's journalistic policies on factual correctness, which aligns with clause 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we comply with Ofcom's decision in its entirety. We will adhere to the sanction as soon as the date and language are finalised."
