The BBC was found to have committed a "serious breach" of industry standards by failing to disclose that the voice of a programme about the Gaza situation was the offspring of a Hamas administrator, according to regulatory body Ofcom.
An investigation by the media regulator into the documentary titled Gaza: How to Survive a Warzone has concluded that the programme was "materially misleading".
The head of the BBC had earlier expressed regret, saying there had been "a significant failing in relation to truthfulness".
The regulator has directed the broadcaster to air a peak-time announcement about its findings.
"As this represents a serious breach of our rules, we are instructing the BBC to broadcast a message of our findings against it on the BBC's second channel at 9pm, with a schedule to be determined," the regulator stated.
'Risk to Damage Confidence'
The regulator's statement said: "Our investigation determined that the documentary's omission to reveal that the presenter's male guardian served in a post in the Hamas-administered government was substantially inaccurate.
"Consequently that the audience did not have vital facts which may have been highly relevant to their evaluation of the narrator and the details he presented.
"Trust is at the center of the bond between a media organization and its public, especially for a state-funded media outlet such as the British Broadcasting Corporation.
"This error had the risk to damage the very considerable levels of credibility that viewers would have placed in a documentary produced by the BBC about the conflict in Gaza."
The documentary was removed from the BBC's streaming service in last February after the boy's familial connections were revealed, and in July an internal BBC review determined it breached the broadcaster's journalistic standards on truthfulness.
A representative for the broadcaster commented: "The regulator's decision is in accordance with the conclusions of the internal assessment, that there was a major oversight in the documentary in relation to the broadcaster's journalistic policies on factual correctness, which reflects clause 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we agree with the regulator's ruling in complete. We will adhere to the sanction as soon as the schedule and language are finalised."
