The BBC engaged in a "significant breach" of industry standards by not revealing that the presenter of a programme about the Gaza situation was the child of a Hamas administrator, as determined by UK media regulator Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has determined that the film was "significantly deceptive".
The chief executive of the broadcaster had previously apologised, saying there had been "a serious error in relation to factual correctness".
Ofcom has directed the broadcaster to transmit a peak-time declaration about its conclusions.
"As this represents a major infringement of our rules, we are instructing the BBC to transmit a message of our findings against it on the BBC's second channel at nine o'clock in the evening, with a date to be confirmed," the regulator stated.
'Possibility to Undermine Trust'
The regulator's statement said: "Our probe found that the programme's omission to reveal that the presenter's father served in a position in the Hamas-run administration was materially misleading.
"Consequently that the viewers did not have critical information which may have been highly relevant to their assessment of the narrator and the information he provided.
"Credibility is at the core of the connection between a broadcaster and its viewers, particularly for a public service broadcaster such as the British Broadcasting Corporation.
"This failing had the potential to erode the very considerable degrees of credibility that viewers would have placed in a factual film from the broadcaster about the Gaza conflict."
The documentary was removed from iPlayer in February after the presenter's family links emerged, and in July an broadcaster's internal assessment found it breached the broadcaster's editorial guidelines on truthfulness.
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 major oversight in the programme in relation to the corporation's content standards on truthfulness, which reflects Rule 2.2 of the regulator's media standards.
"We expressed regret for this and we agree with the regulator's ruling in its entirety. We will follow the directive as soon as the timing and language are confirmed."
