The BBC committed a "major breach" of industry standards by omitting to mention that the presenter of a film about the Gaza situation was the offspring of a Hamas official, according to regulatory body Ofcom.
An investigation by the media regulator into the programme Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The BBC's director general had previously apologised, noting there had been "a significant failing in relation to accuracy".
The regulator has ordered the BBC to transmit a evening announcement about its conclusions.
"Given this constitutes a serious breach of our code, we are ordering the BBC to transmit a announcement of our determinations against it on the BBC's second channel at nine o'clock in the evening, with a timing to be finalised," the regulator stated.
'Possibility to Erode Confidence'
The regulator's announcement declared: "Our investigation determined that the film's failure to disclose that the narrator's parent served in a position in the Hamas-run 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 voice and the information he shared.
"Credibility is at the heart of the relationship between a television network and its public, particularly for a national broadcasting corporation such as the BBC.
"This error had the risk to undermine the exceptionally strong levels of trust that the public would have put in a factual film from the broadcaster about the conflict in Gaza."
The documentary was removed from the BBC's streaming service in February after the presenter's family links emerged, and in July an internal BBC review found it infringed the organization's content policies on truthfulness.
A corporation official said: "The Ofcom ruling is in accordance with the findings of the corporation's inquiry, that there was a serious error in the programme in relation to the BBC's Editorial Guidelines on truthfulness, which reflects clause 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we comply with Ofcom's decision in its entirety. We will adhere to the sanction as soon as the date and wording are finalised."
