The BBC was found to have committed a "serious breach" of media regulations by failing to disclose that the narrator of a documentary about the Gaza situation was the child of a Hamas administrator, as ruled by regulatory body Ofcom.
An investigation by the broadcasting watchdog into Gaza: How to Survive a Warzone has determined that the film was "materially misleading".
The BBC's director general had earlier expressed regret, stating there had been "a major oversight in relation to truthfulness".
Ofcom has directed the broadcaster to transmit a peak-time announcement about its decisions.
"As this represents a major infringement of our code, we are instructing the corporation to broadcast a statement of our conclusions against it on BBC2 at 9pm, with a timing to be finalised," the regulator stated.
'Risk to Erode Confidence'
The regulator's announcement declared: "The inquiry we conducted concluded that the documentary's omission to reveal that the presenter's parent served in a post in the Hamas-controlled administration was materially misleading.
"Consequently that the audience did not have vital facts which may have been extremely pertinent to their evaluation of the narrator and the information he presented.
"Credibility is at the heart of the connection between a broadcaster and its audience, particularly for a national broadcasting corporation such as the BBC.
"This oversight had the risk to undermine the very considerable degrees of trust that the public would have put in a BBC factual programme about the conflict in Gaza."
The programme was withdrawn from the BBC's streaming service in February after the narrator's personal associations came to light, and in July an broadcaster's internal assessment found it breached the corporation's editorial guidelines on truthfulness.
A BBC spokesperson said: "The Ofcom ruling is in accordance with the findings of the internal assessment, that there was a serious error in the documentary in relation to the corporation's content standards on truthfulness, which aligns with Rule 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we comply with the authority's determination in full. We will adhere to the sanction as soon as the timing and wording are determined."
