The BBC engaged in a "major breach" of media regulations by not revealing that the voice of a film about Gaza was the child of a Hamas representative, according to regulatory body Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has found that the documentary was "materially misleading".
The head of the BBC had previously apologised, saying there had been "a major oversight in relation to truthfulness".
The authority has instructed the corporation to transmit a prime-time statement about its decisions.
"Since this amounts to a serious breach of our rules, we are ordering the BBC to transmit a statement of our determinations against it on the BBC's second channel at 9pm, with a timing to be determined," it said.
'Risk to Undermine Credibility'
The authority's statement stated: "Our probe found that the programme's failure to disclose that the voice's male guardian occupied a position in the Hamas-controlled administration was materially misleading.
"This implied that the viewers did not have essential details which may have been highly relevant to their assessment of the voice and the details he provided.
"Credibility is at the heart of the bond between a television network and its viewers, especially for a national broadcasting corporation such as the public broadcaster.
"This error had the potential to erode the exceptionally strong levels of credibility that audiences would have invested in a factual film from the broadcaster about the Gaza conflict."
The documentary was pulled from iPlayer in February after the boy's personal associations were revealed, and in the month of July an corporation's own inquiry concluded it infringed the organization's editorial guidelines on truthfulness.
A representative for the broadcaster stated: "The Ofcom ruling is in agreement with the results of the internal assessment, that there was a significant failing in the programme in relation to the broadcaster's journalistic policies on truthfulness, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we accept Ofcom's decision in complete. We will follow the penalty as soon as the schedule and language are determined."
