The BBC committed a "major breach" of media regulations by omitting to mention that the narrator of a film about Gaza was the son of a Hamas administrator, as ruled by regulatory body Ofcom.
An probe by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has found that the documentary was "materially misleading".
The BBC's director general 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 conclusions.
"As this represents a major infringement of our rules, we are ordering the BBC to transmit a announcement of our findings against it on BBC Two at 21:00, with a date to be confirmed," the statement read.
'Possibility to Undermine Credibility'
The watchdog's statement declared: "The inquiry we conducted determined that the film's omission to reveal that the presenter's parent served in a position in the Hamas-controlled administration was materially misleading.
"This implied that the viewers did not have critical information which may have been highly relevant to their judgment of the voice and the details he provided.
"Credibility is at the center of the relationship between a broadcaster and its viewers, particularly for a public service broadcaster such as the public broadcaster.
"This error had the possibility to erode the very considerable degrees of confidence that audiences would have invested in a BBC factual programme about the Gaza conflict."
The programme was pulled from the online platform in February after the boy's family links emerged, and in July an internal BBC review concluded it violated the corporation's editorial guidelines on truthfulness.
A corporation official said: "The regulator's decision is in line with the conclusions of Peter Johnston's review, that there was a significant failing in the programme in relation to the corporation's content standards on factual correctness, which aligns with clause 2.2 of the regulator's media standards.
"We issued an apology for this and we agree with the regulator's ruling in complete. We will follow the sanction as soon as the date and wording are confirmed."
