The BBC committed a "significant breach" of media regulations by omitting to mention that the narrator of a programme about Gaza was the offspring of a Hamas administrator, according to UK media regulator Ofcom.
An probe by Ofcom into the programme Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, saying there had been "a significant failing in relation to accuracy".
The regulator has ordered the broadcaster to air a evening declaration about its decisions.
"As this represents a major infringement of our code, we are ordering the corporation to transmit a message of our determinations against it on BBC Two at nine o'clock in the evening, with a schedule to be finalised," the statement read.
'Possibility to Erode Confidence'
The watchdog's announcement stated: "The inquiry we conducted found that the documentary's failure to disclose that the voice's parent occupied a role in the Hamas-run authority was materially misleading.
"It meant that the audience did not have critical information which may have been very significant to their assessment of the narrator and the details he shared.
"Trust is at the core of the relationship between a broadcaster and its viewers, especially for a state-funded media outlet such as the public broadcaster.
"This oversight had the possibility to undermine the exceptionally strong levels of confidence that the public would have placed in a BBC factual programme about the conflict in Gaza."
The documentary was removed from iPlayer in the month of February after the narrator's personal associations emerged, and in this past July an internal BBC review found it violated the broadcaster's editorial guidelines on truthfulness.
A BBC spokesperson stated: "The Ofcom ruling is in accordance with the findings of the internal assessment, that there was a major oversight in the film in relation to the BBC's Editorial Guidelines on truthfulness, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we agree with the authority's determination in its entirety. We will comply with the penalty as soon as the schedule and language are confirmed."
