The public service broadcaster was found to have committed a "significant breach" of industry standards by not revealing that the presenter of a film about the Gaza conflict was the offspring of a Hamas official, as determined by British broadcasting authority Ofcom.
An inquiry by the broadcasting watchdog into the documentary titled Gaza: How to Survive a Warzone has found that the documentary was "materially misleading".
The BBC's director general had already issued an apology, saying there had been "a serious error in relation to factual correctness".
Ofcom has instructed the BBC to broadcast a evening announcement about its conclusions.
"Given this constitutes a major infringement of our code, we are instructing the BBC to transmit a message of our conclusions against it on BBC Two at 9pm, with a timing to be finalised," it said.
'Potential to Erode Confidence'
The regulator's announcement stated: "The inquiry we conducted found that the film's failure to disclose that the narrator's father served in a role in the Hamas-controlled government was substantially inaccurate.
"This implied that the public did not have critical information which may have been extremely pertinent to their judgment of the narrator and the details he presented.
"Credibility is at the core of the relationship between a television network and its public, especially for a public service broadcaster such as the public broadcaster.
"This error had the risk to damage the significantly high levels of credibility that audiences would have put in a BBC factual programme about the Israel-Gaza war."
The documentary was pulled from the BBC's streaming service in February after the presenter's familial connections emerged, and in the month of July an internal BBC review determined it violated the broadcaster's editorial guidelines on accuracy.
A corporation official said: "The regulator's decision is in agreement with the results of the corporation's inquiry, that there was a significant failing in the film in relation to the broadcaster's journalistic policies on truthfulness, which aligns with clause 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we comply with the regulator's ruling in complete. We will comply with the penalty as soon as the date and wording are finalised."
