The public service broadcaster committed a "significant breach" of media regulations by omitting to mention that the voice of a documentary about the Gaza conflict was the offspring of a Hamas administrator, as determined by British broadcasting authority Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The head of the BBC had already issued an apology, noting there had been "a significant failing in relation to factual correctness".
The regulator has directed the corporation to broadcast a peak-time announcement about its decisions.
"As this represents a serious breach of our rules, we are ordering the corporation to transmit a message of our determinations against it on the BBC's second channel at 21:00, with a schedule to be finalised," the regulator stated.
'Potential to Erode Confidence'
The regulator's statement declared: "Our investigation concluded that the programme's failure to disclose that the voice's parent occupied a position in the Hamas-run administration was materially misleading.
"This implied that the audience did not have essential details which may have been highly relevant to their judgment of the voice and the information he shared.
"Confidence is at the heart of the connection between a media organization and its audience, particularly for a public service broadcaster such as the British Broadcasting Corporation.
"This failing had the possibility to erode the exceptionally strong degrees of trust that viewers would have placed in a documentary produced by the BBC about the conflict in Gaza."
The programme was withdrawn from iPlayer in last February after the narrator's personal associations were revealed, and in this past July an corporation's own inquiry found it violated the broadcaster's editorial guidelines on truthfulness.
A corporation official stated: "The regulator's decision is in accordance with the results of Peter Johnston's review, that there was a significant failing in the film in relation to the BBC's Editorial Guidelines on accuracy, which reflects clause 2.2 of the regulator's media standards.
"We have apologised for this and we comply with Ofcom's decision in complete. We will follow the penalty as soon as the timing and language are determined."