The BBC engaged in a "serious breach" of industry standards by failing to disclose that the narrator of a film about the Gaza situation was the son of a Hamas official, according to UK media regulator Ofcom.
An probe by the broadcasting watchdog into Gaza: How to Survive a Warzone has determined that the programme was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a significant failing in relation to accuracy".
The regulator has ordered the BBC to transmit a peak-time announcement about its findings.
"Given this constitutes a serious breach of our regulations, we are ordering the corporation to transmit a message of our determinations against it on BBC Two at nine o'clock in the evening, with a timing to be determined," the statement read.
'Potential to Undermine Trust'
The watchdog's announcement said: "Our investigation determined that the programme's lack of disclosure that the voice's father served in a post in the Hamas-controlled government was significantly deceptive.
"This implied that the viewers did not have critical information which may have been highly relevant to their judgment of the narrator and the content he presented.
"Trust is at the center of the bond between a media organization and its viewers, particularly for a public service broadcaster such as the BBC.
"This error had the possibility to undermine the very considerable levels of credibility that the public would have put in a BBC factual programme about the Gaza conflict."
The film was withdrawn from the online platform in February after the boy's familial connections emerged, and in July an broadcaster's internal assessment concluded it violated the corporation's journalistic standards on factual correctness.
A corporation official commented: "The authority's determination is in agreement with the conclusions of the corporation's inquiry, that there was a serious error in the programme in relation to the broadcaster's journalistic policies on factual correctness, which corresponds to Rule 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we agree with the regulator's ruling in full. We will follow the penalty as soon as the timing and wording are finalised."
