The BBC engaged in a "major breach" of industry standards by omitting to mention that the narrator of a programme about Gaza was the son of a Hamas administrator, as ruled by British broadcasting authority Ofcom.
An investigation by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The chief executive of the broadcaster had earlier expressed regret, stating there had been "a major oversight in relation to accuracy".
The authority has instructed the corporation to broadcast a peak-time declaration about its conclusions.
"Given this constitutes a major infringement of our code, we are instructing the corporation to broadcast a message of our findings against it on the BBC's second channel at 21:00, with a schedule to be determined," the statement read.
'Risk to Undermine Credibility'
The watchdog's report said: "Our probe determined that the film's failure to disclose that the voice's male guardian held a position in the Hamas-administered authority was materially misleading.
"Consequently that the audience did not have vital facts which may have been highly relevant to their judgment of the presenter and the content he shared.
"Trust is at the heart of the relationship between a television network and its viewers, particularly for a state-funded media outlet such as the public broadcaster.
"This oversight had the potential to undermine the significantly high degrees of credibility that the public would have placed in a BBC factual programme about the Gaza conflict."
The documentary was pulled from iPlayer in February after the narrator's personal associations were revealed, and in the month of July an internal BBC review determined it violated the broadcaster's content policies on factual correctness.
A representative for the broadcaster commented: "The authority's determination is in accordance with the conclusions of the internal assessment, that there was a serious error in the documentary in relation to the broadcaster's journalistic policies on truthfulness, which corresponds to clause 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we agree with Ofcom's decision in full. We will follow the directive as soon as the date and language are determined."
