The public service broadcaster was found to have committed a "significant breach" of media regulations by omitting to mention that the narrator of a programme about Gaza was the child of a Hamas official, as ruled by UK media regulator Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has concluded that the documentary was "substantially inaccurate".
The chief executive of the broadcaster had earlier expressed regret, stating there had been "a significant failing in relation to accuracy".
The regulator has instructed the corporation to transmit a prime-time declaration about its findings.
"As this represents a serious breach of our rules, we are instructing the broadcaster to broadcast a statement of our conclusions against it on BBC2 at 9pm, with a timing to be finalised," it said.
'Potential to Damage Credibility'
The watchdog's statement stated: "Our investigation found that the documentary's failure to disclose that the presenter's male guardian held a post in the Hamas-administered administration was materially misleading.
"Consequently that the audience did not have critical information which may have been highly relevant to their evaluation of the voice and the details he provided.
"Credibility is at the center of the relationship between a media organization and its viewers, notably for a national broadcasting corporation such as the public broadcaster.
"This error had the risk to undermine the exceptionally strong levels of confidence that viewers would have put in a documentary produced by the BBC about the Gaza conflict."
The programme was pulled from the online platform in February after the presenter's personal associations came to light, and in July an internal BBC review determined it breached the organization's editorial guidelines on factual correctness.
A corporation official said: "The Ofcom ruling is in agreement with the results of the corporation's inquiry, that there was a significant failing in the film in relation to the corporation's content standards on factual correctness, which reflects clause 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we accept Ofcom's decision in complete. We will comply with the penalty as soon as the schedule and wording are confirmed."
