The BBC engaged in a "major breach" of media regulations by not revealing that the voice of a documentary about Gaza was the offspring of a Hamas official, as ruled by UK media regulator Ofcom.
An probe by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has determined that the film was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, saying there had been "a significant failing in relation to factual correctness".
The regulator has ordered the BBC to broadcast a evening declaration about its conclusions.
"As this represents a significant violation of our code, we are directing the broadcaster to transmit a message of our conclusions against it on the BBC's second channel at 9pm, with a schedule to be finalised," the statement read.
'Possibility to Damage Trust'
The watchdog's announcement stated: "Our investigation found that the film's lack of disclosure that the presenter's male guardian held a role in the Hamas-administered administration was substantially inaccurate.
"This implied that the audience did not have vital facts which may have been very significant to their evaluation of the narrator and the details he presented.
"Confidence is at the center of the relationship between a television network and its audience, particularly for a public service broadcaster such as the public broadcaster.
"This error had the risk to erode the exceptionally strong amounts of trust that the public would have invested in a factual film from the broadcaster about the Gaza conflict."
The programme was removed from the online platform in the month of February after the narrator's personal associations were revealed, and in the month of July an internal BBC review concluded it breached the broadcaster's journalistic standards on truthfulness.
A representative for the broadcaster commented: "The authority's determination is in line 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 aligns with Rule 2.2 of the regulator's media standards.
"We expressed regret for this and we agree with the authority's determination in full. We will comply with the sanction as soon as the timing and language are finalised."
