The public service broadcaster engaged in a "significant breach" of industry standards by omitting to mention that the voice of a documentary about the Gaza situation was the offspring of a Hamas administrator, according to regulatory body Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has found that the film was "materially misleading".
The chief executive of the broadcaster had already issued an apology, saying there had been "a serious error in relation to truthfulness".
The authority has instructed the broadcaster to broadcast a evening declaration about its decisions.
"Given this constitutes a serious breach of our regulations, we are ordering the corporation to air a statement of our conclusions against it on BBC2 at 21:00, with a schedule to be determined," it said.
'Potential to Damage Trust'
The watchdog's announcement stated: "The inquiry we conducted concluded that the film's omission to reveal that the narrator's male guardian held a post in the Hamas-run administration was substantially inaccurate.
"This implied that the viewers did not have critical information which may have been very significant to their assessment of the narrator and the details he provided.
"Trust is at the core of the connection between a television network and its viewers, notably for a national broadcasting corporation such as the public broadcaster.
"This failing had the possibility to erode the exceptionally strong degrees of confidence that audiences would have put in a documentary produced by the BBC about the Israel-Gaza war."
The film was pulled from the BBC's streaming service in the month of February after the narrator's family links were revealed, and in July an internal BBC review found it violated the organization's editorial guidelines on truthfulness.
A corporation official stated: "The Ofcom ruling is in line with the results of Peter Johnston's review, that there was a significant failing in the programme in relation to the broadcaster's journalistic policies on accuracy, which aligns with clause 2.2 of the regulator's media standards.
"We expressed regret for this and we accept Ofcom's decision in complete. We will comply with the penalty as soon as the schedule and language are confirmed."
