The BBC engaged in a "serious breach" of broadcasting rules by omitting to mention that the voice of a documentary about Gaza was the child of a Hamas official, according to British broadcasting authority Ofcom.
An investigation by the media regulator into the programme Gaza: How to Survive a Warzone has determined that the film was "materially misleading".
The chief executive of the broadcaster had already issued an apology, saying there had been "a serious error in relation to factual correctness".
Ofcom has instructed the broadcaster to transmit a evening declaration about its conclusions.
"As this represents a significant violation of our code, we are instructing the BBC to air a statement of our findings against it on BBC Two at 21:00, with a timing to be confirmed," the regulator stated.
'Possibility to Undermine Credibility'
The authority's statement stated: "Our probe concluded that the documentary's failure to disclose that the narrator's parent held a role in the Hamas-administered authority was significantly deceptive.
"Consequently that the viewers did not have essential details which may have been very significant to their assessment of the narrator and the information he provided.
"Credibility is at the core of the bond between a media organization and its public, particularly for a national broadcasting corporation such as the public broadcaster.
"This failing had the potential to erode the significantly high levels of confidence that audiences would have put in a BBC factual programme about the conflict in Gaza."
The film was removed from the online platform in the month of February after the narrator's personal associations were revealed, and in the month of July an corporation's own inquiry concluded it infringed the corporation's journalistic standards on factual correctness.
A representative for the broadcaster commented: "The regulator's decision is in line with the results of Peter Johnston's review, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on accuracy, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we accept the regulator's ruling in complete. We will comply with the penalty as soon as the schedule and wording are finalised."
