The BBC committed a "major breach" of media regulations by not revealing that the voice of a programme about the Gaza situation was the offspring of a Hamas representative, according to British broadcasting authority Ofcom.
An probe by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The BBC's director general had earlier expressed regret, stating there had been "a serious error in relation to factual correctness".
The authority has directed the BBC to broadcast a evening statement about its decisions.
"As this represents a serious breach of our code, we are instructing the corporation to transmit a statement of our conclusions against it on BBC Two at nine o'clock in the evening, with a timing to be determined," it said.
'Possibility to Erode Trust'
The watchdog's announcement stated: "Our probe found that the documentary's lack of disclosure that the narrator's parent held a post in the Hamas-run government was significantly deceptive.
"Consequently that the public did not have essential details which may have been highly relevant to their assessment of the voice and the details he presented.
"Trust is at the core of the relationship between a media organization and its viewers, notably for a national broadcasting corporation such as the BBC.
"This failing had the potential to undermine the very considerable amounts of credibility that the public would have put in a documentary produced by the BBC about the Gaza conflict."
The documentary was removed from iPlayer in February after the narrator's familial connections emerged, and in this past July an internal BBC review concluded it violated the corporation's journalistic standards on accuracy.
A representative for the broadcaster stated: "The authority's determination is in line with the findings of the corporation's inquiry, that there was a serious error in the documentary in relation to the corporation's content standards on accuracy, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we agree with the authority's determination in complete. We will comply with the directive as soon as the timing and wording are confirmed."
