The BBC committed a "significant breach" of broadcasting rules by not revealing that the voice of a film about the Gaza situation was the child of a Hamas official, as ruled by regulatory body Ofcom.
An probe by the broadcasting watchdog into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, saying there had been "a serious error in relation to factual correctness".
The authority has instructed the corporation to transmit a prime-time statement about its decisions.
"Since this amounts to a significant violation of our code, we are directing the broadcaster to broadcast a announcement of our findings against it on BBC Two at 9pm, with a timing to be finalised," it said.
'Possibility to Erode Trust'
The regulator's announcement declared: "Our probe found that the programme's omission to reveal that the narrator's parent occupied a post in the Hamas-controlled authority was materially misleading.
"Consequently that the viewers did not have vital facts which may have been very significant to their judgment of the narrator and the information he shared.
"Credibility is at the core of the bond between a broadcaster and its viewers, particularly for a state-funded media outlet such as the BBC.
"This error had the possibility to undermine the very considerable amounts of confidence that audiences would have put in a documentary produced by the BBC about the conflict in Gaza."
The programme was withdrawn from iPlayer in February after the narrator's familial connections came to light, and in this past July an broadcaster's internal assessment concluded it infringed the organization's journalistic standards on factual correctness.
A corporation official commented: "The authority's determination is in accordance with the conclusions of the corporation's inquiry, that there was a significant failing in the programme in relation to the corporation's content standards on factual correctness, which corresponds to Rule 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with Ofcom's decision in its entirety. We will adhere to the penalty as soon as the schedule and wording are finalised."
