The BBC engaged in a "serious breach" of media regulations by failing to disclose that the voice of a documentary about Gaza was the son of a Hamas administrator, as determined by British broadcasting authority Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has found that the film was "materially misleading".
The chief executive of the broadcaster had earlier expressed regret, stating there had been "a major oversight in relation to accuracy".
The regulator has ordered the BBC to broadcast a prime-time announcement about its findings.
"Given this constitutes a significant violation of our code, we are instructing the corporation to air a message of our determinations against it on BBC Two at 21:00, with a schedule to be confirmed," it said.
'Risk to Erode Trust'
The regulator's announcement said: "The inquiry we conducted found that the documentary's omission to reveal that the presenter's father held a post in the Hamas-run government was substantially inaccurate.
"This implied that the audience did not have critical information which may have been very significant to their evaluation of the voice and the information he presented.
"Credibility is at the core of the relationship between a broadcaster and its viewers, particularly for a state-funded media outlet such as the public broadcaster.
"This error had the potential to damage the exceptionally strong amounts of trust that audiences would have put in a BBC factual programme about the conflict in Gaza."
The documentary was removed from iPlayer in February after the boy's familial connections were revealed, and in the month of July an broadcaster's internal assessment determined it infringed the broadcaster's journalistic standards on accuracy.
A corporation official stated: "The authority's determination is in agreement with the results of Peter Johnston's review, that there was a significant failing in the documentary in relation to the corporation's content standards on accuracy, which reflects clause 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we accept the authority's determination in its entirety. We will comply with the directive as soon as the schedule and wording are confirmed."
