The BBC engaged in a "major breach" of broadcasting rules by omitting to mention that the narrator of a documentary about the Gaza situation was the offspring of a Hamas official, according to UK media regulator Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The head of the BBC had earlier expressed regret, saying there had been "a serious error in relation to truthfulness".
The regulator has directed the BBC to transmit a peak-time declaration about its findings.
"As this represents a significant violation of our code, we are directing the BBC to broadcast a message of our determinations against it on BBC2 at nine o'clock in the evening, with a timing to be finalised," the regulator stated.
'Potential to Undermine Confidence'
The regulator's announcement said: "Our investigation concluded that the film's omission to reveal that the narrator's male guardian served in a role in the Hamas-run authority was significantly deceptive.
"Consequently that the public did not have critical information which may have been extremely pertinent to their judgment of the presenter and the details he presented.
"Trust is at the core of the connection between a broadcaster and its viewers, particularly for a public service broadcaster such as the British Broadcasting Corporation.
"This failing had the risk to undermine the significantly high degrees of confidence that viewers would have put in a BBC factual programme about the conflict in Gaza."
The documentary was pulled from the online platform in February after the narrator's personal associations were revealed, and in July an corporation's own inquiry determined it infringed the broadcaster's journalistic standards on truthfulness.
A corporation official said: "The authority's determination is in line with the conclusions of the corporation's inquiry, that there was a major oversight in the film in relation to the corporation's content standards on truthfulness, which reflects regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we comply with the regulator's ruling in full. We will comply with the penalty as soon as the date and wording are finalised."
