The British broadcaster engaged in a "significant breach" of broadcasting rules by omitting to mention that the narrator of a documentary about the Gaza conflict was the offspring of a Hamas representative, according to regulatory body Ofcom.
An probe by the media regulator into Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The chief executive of the broadcaster had already issued an apology, saying there had been "a major oversight in relation to accuracy".
The authority has ordered the broadcaster to air a evening announcement about its findings.
"Given this constitutes a serious breach of our regulations, we are instructing the BBC to air a message of our conclusions against it on BBC2 at nine o'clock in the evening, with a timing to be finalised," the statement read.
'Potential to Erode Trust'
The authority's statement stated: "Our probe concluded that the film's omission to reveal that the narrator's father held a post in the Hamas-administered authority was significantly deceptive.
"Consequently that the public did not have critical information which may have been extremely pertinent to their assessment of the presenter and the content he shared.
"Trust is at the center of the bond between a media organization and its public, notably for a national broadcasting corporation such as the BBC.
"This oversight had the risk to undermine the exceptionally strong degrees of credibility that audiences would have put in a factual film from the broadcaster about the conflict in Gaza."
The documentary was withdrawn from iPlayer in the month of February after the presenter's family links emerged, and in July an broadcaster's internal assessment concluded it breached the organization's editorial guidelines on accuracy.
A BBC spokesperson commented: "The Ofcom ruling is in agreement with the results of the internal assessment, that there was a serious error in the programme in relation to the broadcaster's journalistic policies on truthfulness, which reflects clause 2.2 of the regulator's media standards.
"We issued an apology for this and we accept the authority's determination in its entirety. We will follow the directive as soon as the timing and wording are confirmed."
