The BBC engaged in a "significant breach" of industry standards by omitting to mention that the presenter of a programme about the Gaza situation was the offspring of a Hamas administrator, according to British broadcasting authority Ofcom.
An probe by the broadcasting watchdog into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, stating there had been "a major oversight in relation to truthfulness".
The authority has instructed the broadcaster to broadcast a evening statement about its findings.
"As this represents a major infringement of our rules, we are ordering the BBC to transmit a announcement of our conclusions against it on the BBC's second channel at 21:00, with a date to be confirmed," the regulator stated.
'Potential to Erode Confidence'
The regulator's announcement stated: "Our investigation found that the programme's lack of disclosure that the narrator's male guardian held a position in the Hamas-administered government was significantly deceptive.
"This implied that the viewers did not have critical information which may have been highly relevant to their assessment of the narrator and the information he shared.
"Confidence is at the center of the bond between a broadcaster and its audience, particularly for a state-funded media outlet such as the BBC.
"This failing had the possibility to undermine the significantly high levels of confidence that viewers would have placed in a factual film from the broadcaster about the conflict in Gaza."
The programme was withdrawn from the BBC's streaming service in February after the boy's personal associations emerged, and in this past July an internal BBC review concluded it violated the corporation's content policies on truthfulness.
A corporation official commented: "The Ofcom ruling is in accordance with the results of the corporation's inquiry, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on factual correctness, which aligns with Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we agree with Ofcom's decision in its entirety. We will comply with the penalty as soon as the date and wording are finalised."