The public service broadcaster committed a "significant breach" of industry standards by not revealing that the voice of a film about Gaza was the offspring of a Hamas administrator, according to regulatory body Ofcom.
An inquiry by the broadcasting watchdog into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, stating there had been "a serious error in relation to truthfulness".
Ofcom has directed the broadcaster to air a prime-time announcement about its decisions.
"Given this constitutes a significant violation of our regulations, we are instructing the broadcaster to air a message of our conclusions against it on BBC2 at 9pm, with a date to be determined," it said.
'Risk to Undermine Trust'
The watchdog's announcement said: "The inquiry we conducted concluded that the film's omission to reveal that the presenter's parent occupied a role in the Hamas-controlled authority was substantially inaccurate.
"It meant that the public did not have essential details which may have been extremely pertinent to their judgment of the narrator and the information he shared.
"Confidence is at the core of the connection between a broadcaster and its viewers, notably for a state-funded media outlet such as the British Broadcasting Corporation.
"This oversight had the potential to damage the very considerable levels of confidence that audiences would have invested in a BBC factual programme about the Gaza conflict."
The documentary was pulled from the BBC's streaming service in February after the narrator's family links emerged, and in the month of July an broadcaster's internal assessment concluded it infringed the corporation's journalistic standards on accuracy.
A BBC spokesperson commented: "The Ofcom ruling is in accordance with the conclusions of the corporation's inquiry, that there was a significant failing in the film in relation to the corporation's content standards on accuracy, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we accept the regulator's ruling in its entirety. We will comply with the sanction as soon as the date and language are determined."
