The public service broadcaster was found to have committed a "major breach" of industry standards by not revealing that the narrator of a programme about the Gaza conflict was the child of a Hamas representative, according to regulatory body Ofcom.
An probe by the media regulator into the documentary titled Gaza: How to Survive a Warzone has determined that the film was "materially misleading".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a serious error in relation to factual correctness".
The authority has ordered the broadcaster to air a prime-time declaration about its decisions.
"Since this amounts to a major infringement of our rules, we are ordering the broadcaster to air a announcement of our conclusions against it on BBC2 at nine o'clock in the evening, with a timing to be confirmed," it said.
'Risk to Undermine Trust'
The regulator's statement said: "Our investigation found that the film's lack of disclosure that the narrator's male guardian occupied a position in the Hamas-run authority was materially misleading.
"Consequently that the audience did not have critical information which may have been extremely pertinent to their assessment of the presenter and the information he provided.
"Credibility is at the core of the relationship between a television network and its viewers, especially for a state-funded media outlet such as the BBC.
"This error had the potential to erode the significantly high levels of credibility that viewers would have invested in a BBC factual programme about the Israel-Gaza war."
The documentary was removed from iPlayer in last February after the narrator's family links emerged, and in July an corporation's own inquiry found it infringed the organization's editorial guidelines on truthfulness.
A BBC spokesperson said: "The Ofcom ruling is in agreement with the findings of the corporation's inquiry, that there was a serious error in the film in relation to the corporation's content standards on truthfulness, which aligns with Rule 2.2 of the regulator's media standards.
"We expressed regret for this and we agree with Ofcom's decision in full. We will follow the penalty as soon as the schedule and wording are determined."
