The British broadcaster engaged in a "significant breach" of broadcasting rules by not revealing that the presenter of a programme about Gaza was the offspring of a Hamas representative, as determined by UK media regulator Ofcom.
An probe by the media regulator into Gaza: How to Survive a Warzone has found that the film was "significantly deceptive".
The chief executive of the broadcaster had previously apologised, saying there had been "a significant failing in relation to factual correctness".
Ofcom has directed the broadcaster to air a prime-time announcement about its conclusions.
"Given this constitutes a significant violation of our rules, we are directing the corporation to air a announcement of our findings against it on BBC Two at 21:00, with a schedule to be finalised," the regulator stated.
'Risk to Erode Confidence'
The regulator's report stated: "Our probe determined that the programme's omission to reveal that the presenter's male guardian occupied a position in the Hamas-run authority was substantially inaccurate.
"This implied that the viewers did not have vital facts which may have been extremely pertinent to their assessment of the voice and the content he shared.
"Trust is at the heart of the bond between a broadcaster and its audience, especially for a state-funded media outlet such as the BBC.
"This failing had the potential to damage the very considerable levels of credibility that the public would have placed in a documentary produced by the BBC about the Israel-Gaza war."
The programme was withdrawn from the BBC's streaming service in February after the narrator's family links were revealed, and in July an corporation's own inquiry determined it violated the organization's journalistic standards on accuracy.
A BBC spokesperson commented: "The regulator's decision is in agreement with the findings of the corporation's inquiry, that there was a serious error in the film in relation to the broadcaster's journalistic policies on accuracy, which reflects Rule 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we agree with the authority's determination in complete. We will comply with the penalty as soon as the timing and wording are determined."
