The BBC engaged in a "significant breach" of broadcasting rules by omitting to mention that the voice of a film about Gaza was the offspring of a Hamas official, as ruled by British broadcasting authority Ofcom.
An inquiry by Ofcom into the documentary titled Gaza: How to Survive a Warzone has concluded that the film was "materially misleading".
The BBC's director general had already issued an apology, noting there had been "a significant failing in relation to truthfulness".
The regulator has directed the BBC to broadcast a evening announcement about its findings.
"As this represents a serious breach of our rules, we are directing the corporation to broadcast a announcement of our determinations against it on the BBC's second channel at 21:00, with a schedule to be finalised," it said.
'Possibility to Undermine Confidence'
The watchdog's statement stated: "The inquiry we conducted determined that the programme's lack of disclosure that the narrator's parent occupied a role in the Hamas-controlled administration was substantially inaccurate.
"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 presented.
"Trust is at the center of the relationship between a television network and its viewers, especially for a national broadcasting corporation such as the public broadcaster.
"This failing had the risk to undermine the exceptionally strong degrees of confidence that audiences would have placed in a documentary produced by the BBC about the conflict in Gaza."
The documentary was withdrawn from the BBC's streaming service in last February after the boy's familial connections came to light, and in this past July an corporation's own inquiry found it violated the corporation's content policies on truthfulness.
A corporation official stated: "The Ofcom ruling is in agreement with the findings of Peter Johnston's review, that there was a serious error in the programme in relation to the corporation's content standards on truthfulness, which reflects regulation 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with the authority's determination in complete. We will adhere to the penalty as soon as the date and language are determined."
