The BBC engaged in a "significant breach" of broadcasting rules by not revealing that the voice of a film about the Gaza situation was the child of a Hamas official, as ruled by UK media regulator Ofcom.
An inquiry by Ofcom into the programme Gaza: How to Survive a Warzone has determined that the programme was "significantly deceptive".
The head of the BBC had earlier expressed regret, stating there had been "a major oversight in relation to truthfulness".
The regulator has directed the BBC to broadcast a peak-time announcement about its conclusions.
"Given this constitutes a major infringement of our rules, we are instructing the BBC to transmit a announcement of our findings against it on the BBC's second channel at 9pm, with a date to be determined," the statement read.
'Possibility to Erode Credibility'
The authority's announcement said: "The inquiry we conducted concluded that the documentary's failure to disclose that the presenter's male guardian served in a role in the Hamas-run administration was significantly deceptive.
"This implied that the public did not have vital facts which may have been highly relevant to their evaluation of the voice and the details he provided.
"Confidence is at the heart of the relationship between a broadcaster and its viewers, especially for a public service broadcaster such as the public broadcaster.
"This error had the risk to erode the significantly high levels of credibility that viewers would have put in a factual film from the broadcaster about the Israel-Gaza war."
The film was withdrawn from the online platform in last February after the presenter's personal associations were revealed, and in July an corporation's own inquiry found it violated the corporation's journalistic standards on accuracy.
A corporation official commented: "The authority's determination is in line with the findings of the internal assessment, that there was a serious error in the programme in relation to the broadcaster's journalistic policies on factual correctness, which reflects regulation 2.2 of the regulator's media standards.
"We expressed regret for this and we comply with the regulator's ruling in full. We will comply with the sanction as soon as the date and wording are confirmed."
