The British broadcaster engaged in a "significant breach" of media regulations by not revealing that the presenter of a programme about the Gaza situation was the child of a Hamas representative, according to British broadcasting authority Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has found that the documentary was "significantly deceptive".
The BBC's director general had previously apologised, saying there had been "a significant failing in relation to truthfulness".
The authority has directed the corporation to broadcast a prime-time statement about its decisions.
"Given this constitutes a significant violation of our rules, we are directing the BBC to transmit a announcement of our determinations against it on the BBC's second channel at nine o'clock in the evening, with a timing to be finalised," the statement read.
'Possibility to Damage Credibility'
The watchdog's statement said: "Our investigation found that the film's failure to disclose that the narrator's parent held a post in the Hamas-run authority was materially misleading.
"This implied that the public did not have critical information which may have been highly relevant to their assessment of the narrator and the details he shared.
"Confidence is at the center of the bond between a media organization and its public, notably for a public service broadcaster such as the public broadcaster.
"This failing had the potential to damage the very considerable amounts of credibility that audiences would have placed in a factual film from the broadcaster about the Gaza conflict."
The documentary was removed from the BBC's streaming service in last February after the narrator's family links emerged, and in this past July an corporation's own inquiry found it violated the broadcaster's journalistic standards on truthfulness.
A representative for the broadcaster commented: "The regulator's decision is in line with the findings of the corporation's inquiry, that there was a serious error in the film in relation to the BBC's Editorial Guidelines on truthfulness, which corresponds to clause 2.2 of the regulator's media standards.
"We issued an apology for this and we accept the regulator's ruling in full. We will comply with the penalty as soon as the timing and wording are determined."
