The BBC engaged in a "serious breach" of media regulations by omitting to mention that the presenter of a film about the Gaza conflict was the child of a Hamas official, according to British broadcasting authority Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has found that the programme was "significantly deceptive".
The chief executive of the broadcaster had previously apologised, stating there had been "a serious error in relation to accuracy".
The regulator has directed the BBC to transmit a evening announcement about its findings.
"As this represents a serious breach of our code, we are directing the corporation to transmit a message of our conclusions against it on the BBC's second channel at 21:00, with a date to be determined," it said.
'Potential to Erode Trust'
The regulator's statement said: "Our probe concluded that the film's lack of disclosure that the presenter's parent held a role in the Hamas-controlled authority was substantially inaccurate.
"This implied that the public did not have essential details which may have been extremely pertinent to their assessment of the voice and the information he shared.
"Credibility is at the center of the connection between a television network and its viewers, notably for a state-funded media outlet such as the public broadcaster.
"This error had the risk to erode the very considerable amounts of credibility that the public would have put in a BBC factual programme about the conflict in Gaza."
The documentary was withdrawn from iPlayer in the month of February after the boy's familial connections emerged, and in July an broadcaster's internal assessment determined it breached the corporation's content policies on accuracy.
A corporation official stated: "The authority's determination is in accordance with the results of the internal assessment, that there was a major oversight in the programme in relation to the BBC's Editorial Guidelines on accuracy, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we comply with the regulator's ruling in full. We will adhere to the penalty as soon as the timing and language are finalised."
