The British broadcaster engaged in a "significant breach" of industry standards by not revealing that the voice of a programme about Gaza was the son of a Hamas official, according to British broadcasting authority Ofcom.
An probe by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has determined that the programme was "substantially inaccurate".
The BBC's director general had previously apologised, saying there had been "a serious error in relation to factual correctness".
The regulator has instructed the broadcaster to transmit a prime-time declaration about its findings.
"Since this amounts to a major infringement of our regulations, we are directing the broadcaster to air a announcement of our conclusions against it on the BBC's second channel at 21:00, with a schedule to be finalised," the regulator stated.
'Possibility to Erode Credibility'
The watchdog's report said: "Our probe concluded that the film's lack of disclosure that the presenter's parent occupied a post in the Hamas-administered administration was significantly deceptive.
"This implied that the viewers did not have critical information which may have been very significant to their judgment of the presenter and the details he provided.
"Credibility is at the core of the bond between a broadcaster and its viewers, particularly for a public service broadcaster such as the British Broadcasting Corporation.
"This error had the possibility to damage the exceptionally strong amounts of trust that audiences would have placed in a BBC factual programme about the Gaza conflict."
The film was pulled from iPlayer in February after the boy's personal associations emerged, and in July an corporation's own inquiry concluded it breached the broadcaster's journalistic standards on truthfulness.
A representative for the broadcaster said: "The authority's determination is in line with the findings of the internal assessment, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we agree with the authority's determination in complete. We will comply with the penalty as soon as the date and language are determined."
