The BBC engaged in a "serious breach" of broadcasting rules by not revealing that the voice of a film about Gaza was the child of a Hamas administrator, as ruled by regulatory body Ofcom.
An inquiry by Ofcom into the documentary titled Gaza: How to Survive a Warzone has found that the documentary was "significantly deceptive".
The BBC's director general had earlier expressed regret, saying there had been "a major oversight in relation to truthfulness".
The authority has ordered the BBC to broadcast a peak-time statement about its findings.
"As this represents a major infringement of our code, we are ordering the corporation to transmit a announcement of our findings against it on the BBC's second channel at nine o'clock in the evening, with a schedule to be finalised," it said.
'Possibility to Erode Confidence'
The watchdog's statement stated: "Our investigation found that the film's failure to disclose that the narrator's male guardian occupied a role in the Hamas-administered authority was materially misleading.
"This implied that the audience did not have vital facts which may have been extremely pertinent to their assessment of the voice and the details he shared.
"Confidence is at the core of the bond between a media organization and its public, particularly for a public service broadcaster such as the BBC.
"This error had the possibility to damage the significantly high degrees of credibility that viewers would have invested in a BBC factual programme about the Gaza conflict."
The documentary was pulled from the BBC's streaming service in last February after the presenter's familial connections emerged, and in July an broadcaster's internal assessment found it infringed the broadcaster's content policies on accuracy.
A corporation official said: "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 corporation's content standards on accuracy, which corresponds to regulation 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we accept the authority's determination in its entirety. We will comply with the directive as soon as the timing and wording are confirmed."
