The BBC engaged in a "serious breach" of broadcasting rules by not revealing that the presenter of a film about the Gaza situation was the child of a Hamas administrator, according to regulatory body Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has concluded that the programme was "materially misleading".
The head of the BBC had already issued an apology, saying there had been "a serious error in relation to accuracy".
The regulator has ordered the broadcaster to broadcast a prime-time declaration about its findings.
"Since this amounts to a major infringement of our regulations, we are ordering the BBC to broadcast a announcement of our determinations against it on BBC Two at 21:00, with a timing to be finalised," it said.
'Potential to Erode Confidence'
The regulator's report declared: "Our investigation determined that the documentary's failure to disclose that the voice's parent held a post in the Hamas-controlled authority was significantly deceptive.
"This implied that the audience did not have vital facts which may have been very significant to their judgment of the voice and the information he provided.
"Confidence is at the core of the relationship between a media organization and its public, particularly for a national broadcasting corporation such as the British Broadcasting Corporation.
"This oversight had the potential to erode the exceptionally strong degrees of credibility that audiences would have put in a BBC factual programme about the Israel-Gaza war."
The documentary was pulled from the BBC's streaming service in the month of February after the boy's family links were revealed, and in the month of July an broadcaster's internal assessment found it infringed the broadcaster's editorial guidelines on truthfulness.
A BBC spokesperson commented: "The Ofcom ruling is in agreement with the conclusions of the corporation's inquiry, that there was a serious error in the documentary in relation to the corporation's content standards on factual correctness, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we comply with Ofcom's decision in full. We will follow the penalty as soon as the date and wording are confirmed."
