The BBC was found to have committed a "major breach" of media regulations by omitting to mention that the voice of a documentary about the Gaza situation was the offspring of a Hamas representative, as ruled by UK media regulator Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has found that the documentary was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, stating there had been "a major oversight in relation to accuracy".
Ofcom has directed the BBC to transmit a peak-time announcement about its decisions.
"Given this constitutes a significant violation of our rules, we are directing the corporation to broadcast a announcement of our conclusions against it on BBC Two at nine o'clock in the evening, with a timing to be finalised," the regulator stated.
'Risk to Damage Credibility'
The authority's announcement said: "Our investigation found that the documentary's failure to disclose that the voice's male guardian occupied a position in the Hamas-controlled authority was significantly deceptive.
"This implied that the public did not have critical information which may have been extremely pertinent to their assessment of the presenter and the content he provided.
"Confidence is at the heart of the relationship between a television network and its viewers, particularly for a state-funded media outlet such as the BBC.
"This oversight had the potential to damage the exceptionally strong degrees of trust that the public would have placed in a factual film from the broadcaster about the Israel-Gaza war."
The documentary was removed from the BBC's streaming service in February after the narrator's familial connections were revealed, and in July an broadcaster's internal assessment found it violated the broadcaster's journalistic standards on truthfulness.
A BBC spokesperson stated: "The regulator's decision is in line with the findings of Peter Johnston's review, that there was a major oversight in the film in relation to the broadcaster's journalistic policies on accuracy, which aligns with clause 2.2 of the regulator's media standards.
"We issued an apology for this and we accept Ofcom's decision in full. We will follow the penalty as soon as the date and wording are determined."
