The BBC committed a "major breach" of industry standards by not revealing that the presenter of a programme about Gaza was the child of a Hamas official, as determined by British broadcasting authority Ofcom.
An probe by the media regulator into the documentary titled Gaza: How to Survive a Warzone has found that the documentary was "significantly deceptive".
The BBC's director general had earlier expressed regret, saying there had been "a serious error in relation to factual correctness".
The regulator has directed the broadcaster to air a peak-time declaration about its conclusions.
"Since this amounts to a major infringement of our regulations, we are ordering the corporation to broadcast a message of our findings against it on the BBC's second channel at 9pm, with a schedule to be finalised," the statement read.
The regulator's report stated: "The inquiry we conducted determined that the documentary's omission to reveal that the presenter's parent occupied a role in the Hamas-controlled authority was materially misleading.
"This implied that the public did not have vital facts which may have been very significant to their judgment of the presenter and the content he shared.
"Trust is at the heart of the connection between a media organization and its public, notably for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the possibility to undermine the very considerable levels of credibility that viewers would have placed in a documentary produced by the BBC about the conflict in Gaza."
The film was removed from the online platform in February after the boy's personal associations were revealed, and in July an corporation's own inquiry found it infringed the organization's journalistic standards on accuracy.
A corporation official said: "The authority's determination is in agreement with the findings of the corporation's inquiry, that there was a serious error in the documentary in relation to the broadcaster's journalistic policies on accuracy, which corresponds to clause 2.2 of the regulator's media standards.
"We issued an apology for this and we comply with Ofcom's decision in complete. We will adhere to the sanction as soon as the schedule and language are confirmed."
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