The BBC engaged in a "serious breach" of media regulations by not revealing that the presenter of a documentary about the Gaza conflict was the child of a Hamas official, as ruled by UK media regulator Ofcom.
An investigation by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the film was "significantly deceptive".
The BBC's director general had already issued an apology, noting there had been "a serious error in relation to factual correctness".
Ofcom has ordered the corporation to air a peak-time announcement about its decisions.
"Given this constitutes a major infringement of our rules, we are instructing the corporation to air a announcement of our determinations against it on BBC Two at 9pm, with a schedule to be finalised," it said.
'Risk to Erode Confidence'
The authority's report said: "The inquiry we conducted found that the film's omission to reveal that the voice's male guardian held a role in the Hamas-administered administration was significantly deceptive.
"It meant that the viewers did not have vital facts which may have been extremely pertinent to their evaluation of the narrator and the details he presented.
"Credibility is at the core of the connection between a media organization and its audience, particularly for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the possibility to damage the very considerable amounts of trust that audiences would have put in a factual film from the broadcaster about the Israel-Gaza war."
The film was pulled from iPlayer in last February after the boy's familial connections were revealed, and in July an broadcaster's internal assessment found it infringed the organization's journalistic standards on truthfulness.
A corporation official commented: "The Ofcom ruling is in accordance with the results of the internal assessment, that there was a major oversight in the film in relation to the BBC's Editorial Guidelines on factual correctness, which corresponds to Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we comply with Ofcom's decision in complete. We will comply with the penalty as soon as the date and wording are determined."
