The BBC committed a "significant breach" of media regulations by not revealing that the narrator of a film about the Gaza situation was the child of a Hamas representative, as ruled by UK media regulator Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has concluded that the documentary was "substantially inaccurate".
The chief executive of the broadcaster had previously apologised, noting there had been "a major oversight in relation to accuracy".
The regulator has directed the corporation to broadcast a prime-time announcement about its findings.
"Given this constitutes a significant violation of our rules, we are instructing the BBC to air a statement of our conclusions against it on the BBC's second channel at nine o'clock in the evening, with a schedule to be finalised," it said.
'Risk to Undermine Credibility'
The watchdog's statement stated: "The inquiry we conducted concluded that the programme's failure to disclose that the voice's father served in a position in the Hamas-controlled government was materially misleading.
"It meant that the viewers did not have critical information which may have been highly relevant to their evaluation of the voice and the details he provided.
"Confidence is at the heart of the bond between a television network and its viewers, especially for a public service broadcaster such as the BBC.
"This error had the risk to erode the significantly high levels of confidence that audiences would have invested in a factual film from the broadcaster about the conflict in Gaza."
The documentary was withdrawn from iPlayer in the month of February after the boy's familial connections came to light, and in the month of July an corporation's own inquiry determined it breached the broadcaster's content policies on factual correctness.
A BBC spokesperson commented: "The Ofcom ruling is in accordance with the results of the internal assessment, that there was a major oversight in the programme in relation to the corporation's content standards on factual correctness, which aligns with clause 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we accept the authority's determination in complete. We will follow the penalty as soon as the date and wording are finalised."
