The BBC engaged in a "significant breach" of media regulations by failing to disclose that the presenter of a documentary about the Gaza situation was the child of a Hamas official, as ruled by British broadcasting authority Ofcom.
An inquiry by the media regulator into Gaza: How to Survive a Warzone has determined that the film was "significantly deceptive".
The BBC's director general had already issued an apology, saying there had been "a major oversight in relation to truthfulness".
The regulator has directed the broadcaster to broadcast a peak-time declaration about its conclusions.
"As this represents a significant violation of our regulations, we are instructing the corporation to broadcast a statement of our conclusions against it on BBC Two at 9pm, with a schedule to be confirmed," it said.
'Possibility to Damage Trust'
The watchdog's announcement stated: "Our probe concluded that the film's failure to disclose that the narrator's parent served in a role in the Hamas-administered authority was materially misleading.
"Consequently that the audience did not have vital facts which may have been extremely pertinent to their assessment of the presenter and the details he presented.
"Confidence is at the heart of the connection between a television network and its audience, notably for a state-funded media outlet such as the public broadcaster.
"This oversight had the possibility to damage the exceptionally strong degrees of trust that the public would have invested in a documentary produced by the BBC about the conflict in Gaza."
The programme was withdrawn from iPlayer in February after the boy's personal associations were revealed, and in July an broadcaster's internal assessment found it infringed the organization's content policies on factual correctness.
A representative for the broadcaster stated: "The authority's determination is in agreement with the conclusions of the corporation's inquiry, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on accuracy, which corresponds to Rule 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we agree with Ofcom's decision in full. We will comply with the penalty as soon as the schedule and wording are determined."
