The public service broadcaster engaged in a "serious breach" of media regulations by failing to disclose that the voice of a programme about the Gaza conflict was the child of a Hamas administrator, according to UK media regulator Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has determined that the film was "significantly deceptive".
The BBC's director general had previously apologised, stating there had been "a serious error in relation to truthfulness".
The authority has directed the corporation to air a evening statement about its conclusions.
"Since this amounts to a significant violation of our rules, we are instructing the broadcaster to air a announcement of our determinations against it on BBC Two at 21:00, with a date to be determined," it said.
'Risk to Erode Trust'
The watchdog's statement stated: "Our investigation found that the documentary's omission to reveal that the narrator's male guardian held a role in the Hamas-controlled government was substantially inaccurate.
"This implied that the viewers did not have essential details which may have been highly relevant to their judgment of the presenter and the information he shared.
"Credibility is at the core of the relationship between a television network and its viewers, notably for a state-funded media outlet such as the public broadcaster.
"This error had the possibility to undermine the exceptionally strong levels of trust that the public would have placed in a factual film from the broadcaster about the Gaza conflict."
The programme was removed from the BBC's streaming service in February after the boy's personal associations were revealed, and in July an broadcaster's internal assessment determined it breached the corporation's editorial guidelines on accuracy.
A corporation official stated: "The regulator's decision is in accordance with the findings 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 Rule 2.2 of the regulator's media standards.
"We have apologised for this and we accept the regulator's ruling in full. We will adhere to the sanction as soon as the timing and wording are confirmed."
