The British broadcaster committed a "major breach" of media regulations by failing to disclose that the presenter of a film about the Gaza conflict was the son of a Hamas representative, as determined by UK media regulator Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The BBC's director general had earlier expressed regret, noting there had been "a significant failing in relation to truthfulness".
Ofcom has ordered the broadcaster to air a prime-time announcement about its findings.
"As this represents a major infringement of our code, we are ordering the broadcaster to transmit a statement of our determinations against it on BBC2 at nine o'clock in the evening, with a timing to be confirmed," it said.
'Risk to Erode Confidence'
The watchdog's statement said: "Our probe determined that the programme's lack of disclosure that the narrator's parent occupied a role in the Hamas-run government was substantially inaccurate.
"It meant that the viewers did not have critical information which may have been extremely pertinent to their evaluation of the narrator and the content he provided.
"Trust is at the heart of the relationship between a media organization and its viewers, notably for a state-funded media outlet such as the BBC.
"This oversight had the possibility to undermine the significantly high amounts of credibility that audiences would have invested in a documentary produced by the BBC about the Gaza conflict."
The film was removed from the BBC's streaming service in February after the presenter's familial connections came to light, and in July an internal BBC review concluded it violated the organization's editorial guidelines on truthfulness.
A corporation official said: "The regulator's decision is in agreement with the findings of the corporation's inquiry, that there was a significant failing in the documentary in relation to the corporation's content standards on truthfulness, which corresponds to regulation 2.2 of the regulator's media standards.
"We have apologised for this and we agree with Ofcom's decision in its entirety. We will follow the penalty as soon as the date and wording are finalised."
