The BBC engaged in a "major breach" of broadcasting rules by failing to disclose that the presenter of a programme about Gaza was the offspring of a Hamas representative, according to regulatory body Ofcom.
An inquiry by the broadcasting watchdog into Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The BBC's director general had earlier expressed regret, saying there had been "a major oversight in relation to accuracy".
Ofcom has instructed the broadcaster to transmit a prime-time statement about its conclusions.
"As this represents a significant violation of our rules, we are ordering the corporation to transmit a statement of our findings against it on BBC2 at 9pm, with a timing to be confirmed," it said.
'Possibility to Erode Credibility'
The watchdog's report said: "The inquiry we conducted found that the film's failure to disclose that the presenter's male guardian occupied a post in the Hamas-administered administration was significantly deceptive.
"It meant that the public did not have critical information which may have been extremely pertinent to their judgment of the narrator and the content he shared.
"Confidence is at the heart of the connection between a broadcaster and its audience, especially for a state-funded media outlet such as the British Broadcasting Corporation.
"This error had the possibility to undermine the significantly high amounts of trust that the public would have invested in a documentary produced by the BBC about the Israel-Gaza war."
The programme was withdrawn from the online platform in February after the boy's familial connections emerged, and in July an broadcaster's internal assessment concluded it violated the organization's editorial guidelines on truthfulness.
A corporation official stated: "The Ofcom ruling is in line with the conclusions of the corporation's inquiry, that there was a significant failing in the documentary in relation to the BBC's Editorial Guidelines on factual correctness, which aligns with regulation 2.2 of the regulator's media standards.
"We issued an apology for this and we accept Ofcom's decision in its entirety. We will comply with the sanction as soon as the date and language are finalised."
