The BBC engaged in a "serious breach" of broadcasting rules by not revealing that the voice of a programme about the Gaza conflict was the child of a Hamas official, as determined by regulatory body Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The head of the BBC had previously apologised, noting there had been "a significant failing in relation to truthfulness".
Ofcom has directed the broadcaster to broadcast a prime-time statement about its decisions.
"Since this amounts to a significant violation of our rules, we are directing the broadcaster to air a statement of our conclusions against it on the BBC's second channel at 21:00, with a timing to be determined," it said.
'Possibility to Erode Confidence'
The authority's statement said: "Our probe found that the documentary's failure to disclose that the narrator's father held a position in the Hamas-run administration was significantly deceptive.
"It meant that the viewers did not have vital facts which may have been very significant to their assessment of the narrator and the content he provided.
"Confidence is at the center of the connection between a broadcaster and its public, especially for a national broadcasting corporation such as the BBC.
"This oversight had the risk to undermine the very considerable amounts of confidence that viewers would have placed in a BBC factual programme about the Gaza conflict."
The film was pulled from the online platform in February after the narrator's family links were revealed, and in this past July an internal BBC review found it breached the organization's editorial guidelines on accuracy.
A corporation official stated: "The regulator's decision is in line with the results of Peter Johnston's review, that there was a major oversight in the documentary in relation to the corporation's content standards on accuracy, which corresponds to regulation 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept the authority's determination in full. We will adhere to the directive as soon as the timing and wording are finalised."
