The BBC committed a "significant breach" of broadcasting rules by omitting to mention that the narrator of a programme about the Gaza conflict was the offspring of a Hamas administrator, as determined by regulatory body Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The BBC's director general had already issued an apology, noting there had been "a major oversight in relation to accuracy".
The authority has instructed the BBC to broadcast a peak-time declaration about its conclusions.
"Since this amounts to a significant violation of our regulations, we are instructing the BBC to transmit a message of our conclusions against it on BBC Two at nine o'clock in the evening, with a date to be finalised," the statement read.
'Risk to Erode Confidence'
The watchdog's report said: "Our investigation determined that the documentary's lack of disclosure that the presenter's parent served in a position in the Hamas-administered administration was significantly deceptive.
"Consequently that the public did not have critical information which may have been highly relevant to their assessment of the presenter and the content he provided.
"Credibility is at the core of the bond between a broadcaster and its viewers, especially for a state-funded media outlet such as the BBC.
"This failing had the possibility to erode the very considerable levels of confidence that audiences would have placed in a documentary produced by the BBC about the conflict in Gaza."
The documentary was pulled from the BBC's streaming service in February after the boy's familial connections came to light, and in July an internal BBC review found it breached the broadcaster's content policies on truthfulness.
A corporation official commented: "The Ofcom ruling is in line with the findings of the corporation's inquiry, that there was a significant failing in the documentary in relation to the broadcaster's journalistic policies on factual correctness, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we accept Ofcom's decision in full. We will comply with the directive as soon as the timing and wording are determined."
