The British broadcaster engaged in a "major breach" of broadcasting rules by not revealing that the presenter of a film about Gaza was the son of a Hamas administrator, as determined by regulatory body Ofcom.
An inquiry by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has found that the programme was "significantly deceptive".
The chief executive of the broadcaster had already issued an apology, stating there had been "a serious error in relation to accuracy".
Ofcom has directed the corporation to transmit a peak-time announcement about its findings.
"Given this constitutes a significant violation of our regulations, we are instructing the BBC to air 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 determined," the statement read.
'Possibility to Undermine Credibility'
The watchdog's report said: "The inquiry we conducted concluded that the programme's failure to disclose that the voice's male guardian served in a role in the Hamas-controlled government was substantially inaccurate.
"It meant that the audience did not have critical information which may have been highly relevant to their evaluation of the narrator and the details he shared.
"Trust is at the heart of the bond between a broadcaster and its public, especially for a public service broadcaster such as the BBC.
"This error had the possibility to undermine the very considerable degrees of credibility that viewers would have put in a factual film from the broadcaster about the Gaza conflict."
The film was withdrawn from the BBC's streaming service in the month of February after the narrator's familial connections were revealed, and in the month of July an internal BBC review found it violated the broadcaster's editorial guidelines on accuracy.
A BBC spokesperson said: "The Ofcom ruling is in accordance with the results of Peter Johnston's review, that there was a serious error in the programme in relation to the corporation's content standards on factual correctness, which corresponds to clause 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we accept the authority's determination in full. We will follow the sanction as soon as the date and language are determined."
