The public service broadcaster was found to have committed a "significant breach" of broadcasting rules by not revealing that the voice of a documentary about Gaza was the offspring of a Hamas representative, according to British broadcasting authority Ofcom.
An investigation by Ofcom into the programme Gaza: How to Survive a Warzone has determined that the programme was "substantially inaccurate".
The BBC's director general had already issued an apology, noting there had been "a serious error in relation to accuracy".
Ofcom has ordered the BBC to broadcast a peak-time announcement about its findings.
"Since this amounts to a significant violation of our rules, we are directing the BBC to transmit a announcement of our conclusions against it on BBC2 at 21:00, with a date to be finalised," the regulator stated.
The authority's statement said: "Our investigation concluded that the documentary's failure to disclose that the narrator's male guardian held a post in the Hamas-run government was materially misleading.
"Consequently that the public did not have vital facts which may have been highly relevant to their judgment of the presenter and the details he shared.
"Confidence is at the core of the relationship between a broadcaster and its public, particularly for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the potential to undermine the very considerable degrees of confidence that audiences would have put in a factual film from the broadcaster about the conflict in Gaza."
The film was withdrawn from the online platform in the month of February after the narrator's family links were revealed, and in this past July an broadcaster's internal assessment found it infringed the organization's editorial guidelines on truthfulness.
A BBC spokesperson stated: "The authority's determination is in accordance with the results of Peter Johnston's review, that there was a serious error in the film in relation to the broadcaster's journalistic policies on accuracy, which aligns with Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we agree with the authority's determination in full. We will adhere to the penalty as soon as the timing and language are finalised."
