The BBC committed a "major breach" of media regulations by failing to disclose that the presenter of a film about the Gaza situation 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 found that the documentary was "significantly deceptive".
The BBC's director general had earlier expressed regret, stating there had been "a major oversight in relation to accuracy".
The regulator has instructed the corporation to transmit a peak-time declaration about its decisions.
"Since this amounts to a serious breach of our regulations, we are ordering the BBC to transmit a announcement of our findings against it on the BBC's second channel at nine o'clock in the evening, with a date to be determined," it said.
'Potential to Damage Credibility'
The watchdog's announcement declared: "The inquiry we conducted concluded that the documentary's lack of disclosure that the voice's father held a post in the Hamas-controlled government was materially misleading.
"It meant that the audience did not have critical information which may have been extremely pertinent to their evaluation of the voice and the information he presented.
"Credibility is at the core of the relationship between a media organization and its audience, especially for a state-funded media outlet such as the BBC.
"This failing had the potential to erode the very considerable levels of credibility that audiences would have put in a BBC factual programme about the Gaza conflict."
The documentary was removed from the BBC's streaming service in February after the narrator's personal associations came to light, and in the month of July an corporation's own inquiry determined it violated the broadcaster's editorial guidelines on accuracy.
A representative for the broadcaster said: "The Ofcom ruling is in agreement with the findings of Peter Johnston's review, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which aligns with clause 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we comply with the authority's determination in complete. We will adhere to the directive as soon as the timing and wording are determined."
