The BBC committed a "serious breach" of broadcasting rules by not revealing that the voice of a documentary about Gaza was the son of a Hamas administrator, according to British broadcasting authority Ofcom.
An inquiry by the media regulator into Gaza: How to Survive a Warzone has determined that the documentary was "materially misleading".
The head of the BBC had previously apologised, stating there had been "a significant failing in relation to truthfulness".
The authority has directed the broadcaster to transmit a peak-time declaration about its findings.
"Since this amounts to a serious breach of our rules, we are directing the corporation to transmit a announcement of our determinations against it on BBC Two at nine o'clock in the evening, with a schedule to be determined," it said.
'Risk to Undermine Credibility'
The authority's announcement stated: "The inquiry we conducted found that the film's omission to reveal that the voice's father occupied a position in the Hamas-controlled government was materially misleading.
"This implied that the viewers did not have essential details which may have been very significant to their assessment of the presenter and the content he presented.
"Confidence is at the core of the relationship between a broadcaster and its viewers, especially for a state-funded media outlet such as the British Broadcasting Corporation.
"This error had the possibility to damage the significantly high degrees of confidence that audiences would have invested in a BBC factual programme about the Gaza conflict."
The programme was withdrawn from the BBC's streaming service in the month of February after the narrator's familial connections emerged, and in July an broadcaster's internal assessment determined it infringed the organization's journalistic standards on accuracy.
A corporation official commented: "The Ofcom ruling is in line with the conclusions of the corporation's inquiry, that there was a significant failing in the film in relation to the corporation's content standards on truthfulness, which corresponds to Rule 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we comply with the regulator's ruling in complete. We will follow the sanction as soon as the date and wording are finalised."
