The public service broadcaster engaged in a "major breach" of broadcasting rules by not revealing that the voice of a documentary about the Gaza situation was the son of a Hamas representative, as determined by regulatory body Ofcom.
An investigation by Ofcom into the documentary titled Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The BBC's director general had already issued an apology, stating there had been "a significant failing in relation to accuracy".
The regulator has instructed the BBC to air a evening announcement about its findings.
"Since this amounts to a serious breach of our regulations, we are directing the corporation to transmit a message of our conclusions against it on the BBC's second channel at 21:00, with a date to be confirmed," the statement read.
'Potential to Undermine Credibility'
The watchdog's report stated: "The inquiry we conducted determined that the programme's omission to reveal that the narrator's male guardian occupied a post in the Hamas-controlled administration was materially misleading.
"It meant that the viewers did not have critical information which may have been highly relevant to their judgment of the presenter and the information he shared.
"Confidence is at the center of the connection between a broadcaster and its public, especially for a national broadcasting corporation such as the BBC.
"This oversight had the possibility to damage the very considerable amounts of trust that the public would have invested in a factual film from the broadcaster about the Israel-Gaza war."
The programme was pulled from iPlayer in the month of February after the narrator's family links emerged, and in the month of July an corporation's own inquiry found it breached the broadcaster's journalistic standards on truthfulness.
A BBC spokesperson said: "The authority's determination is in line with the conclusions of the corporation's inquiry, that there was a major oversight in the documentary in relation to the broadcaster's journalistic policies on truthfulness, which aligns with regulation 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we accept the authority's determination in complete. We will follow the penalty as soon as the date and wording are confirmed."
