The BBC engaged in a "serious breach" of media regulations by omitting to mention that the presenter of a documentary about Gaza was the child of a Hamas administrator, as determined by regulatory body Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has determined that the film was "significantly deceptive".
The BBC's director general had already issued an apology, noting there had been "a major oversight in relation to accuracy".
The regulator has ordered the corporation to air a peak-time announcement about its findings.
"Since this amounts to a major infringement of our rules, we are instructing the corporation to transmit a statement of our determinations against it on the BBC's second channel at 21:00, with a date to be finalised," the statement read.
'Risk to Damage Credibility'
The watchdog's statement said: "Our probe found that the film's omission to reveal that the presenter's father occupied a post in the Hamas-administered administration was significantly deceptive.
"It meant that the viewers did not have critical information which may have been highly relevant to their evaluation of the narrator and the information he presented.
"Trust is at the heart of the connection between a broadcaster and its public, notably for a national broadcasting corporation such as the British Broadcasting Corporation.
"This failing had the possibility to damage the exceptionally strong levels of credibility that the public would have put in a BBC factual programme about the Israel-Gaza war."
The documentary was pulled from iPlayer in February after the narrator's personal associations emerged, and in this past July an corporation's own inquiry determined it infringed the corporation's content policies on truthfulness.
A corporation official stated: "The regulator's decision is in agreement with the findings of the internal assessment, that there was a significant failing in the documentary in relation to the corporation's content standards on accuracy, which corresponds to clause 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we accept the authority's determination in complete. We will comply with the sanction as soon as the timing and wording are finalised."
