The BBC was found to have committed a "serious breach" of media regulations by not revealing that the voice of a film about the Gaza situation was the offspring of a Hamas administrator, as ruled by UK media regulator Ofcom.
An investigation by Ofcom into the programme Gaza: How to Survive a Warzone has found that the programme was "significantly deceptive".
The BBC's director general had earlier expressed regret, saying there had been "a significant failing in relation to accuracy".
The authority has directed the broadcaster to air a peak-time announcement about its decisions.
"As this represents a serious breach of our regulations, we are directing the corporation to transmit a announcement of our determinations against it on BBC2 at nine o'clock in the evening, with a date to be determined," it said.
'Potential to Erode Credibility'
The watchdog's statement declared: "Our investigation found that the documentary's failure to disclose that the narrator's male guardian held a position in the Hamas-administered administration was materially misleading.
"It meant that the audience did not have vital facts which may have been very significant to their evaluation of the voice and the content he shared.
"Trust is at the core of the connection between a television network and its audience, particularly for a national broadcasting corporation such as the public broadcaster.
"This error had the potential to undermine the exceptionally strong degrees of confidence that viewers would have placed in a factual film from the broadcaster about the Gaza conflict."
The programme was pulled from the online platform in the month of February after the narrator's personal associations came to light, and in the month of July an broadcaster's internal assessment determined it breached the corporation's journalistic standards on accuracy.
A corporation official commented: "The authority's determination is in agreement with the findings of Peter Johnston's review, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which aligns with Rule 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept the authority's determination in full. We will follow the penalty as soon as the schedule and wording are determined."
