The public service broadcaster engaged in a "major breach" of media regulations by not revealing that the voice of a film about the Gaza conflict was the child of a Hamas representative, as determined by regulatory body Ofcom.
An investigation by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The BBC's director general had earlier expressed regret, stating there had been "a serious error in relation to truthfulness".
Ofcom has directed the broadcaster to air a prime-time declaration about its decisions.
"As this represents a significant violation of our regulations, we are instructing the broadcaster to transmit a statement of our conclusions against it on BBC2 at 9pm, with a date to be confirmed," the statement read.
'Risk to Erode Confidence'
The authority's statement stated: "Our probe concluded that the film's failure to disclose that the narrator's father held a position in the Hamas-administered authority was substantially inaccurate.
"This implied that the viewers did not have vital facts which may have been very significant to their evaluation of the narrator and the information he presented.
"Confidence is at the core of the connection between a television network and its audience, particularly for a public service broadcaster such as the British Broadcasting Corporation.
"This oversight had the potential to damage the exceptionally strong degrees of credibility that viewers would have placed in a BBC factual programme about the conflict in Gaza."
The documentary was withdrawn from iPlayer in last February after the presenter's family links were revealed, and in this past July an corporation's own inquiry concluded it violated the broadcaster's editorial guidelines on factual correctness.
A corporation official commented: "The authority's determination is in line with the results of Peter Johnston's review, that there was a significant failing in the documentary in relation to the broadcaster's journalistic policies on truthfulness, which corresponds to Rule 2.2 of the regulator's media standards.
"We expressed regret for this and we comply with the regulator's ruling in complete. We will comply with the penalty as soon as the timing and wording are confirmed."
