The British broadcaster was found to have committed a "serious breach" of broadcasting rules by not revealing that the narrator of a film about the Gaza conflict was the son of a Hamas administrator, according to regulatory body Ofcom.
An inquiry by Ofcom into the programme Gaza: How to Survive a Warzone has found that the documentary was "materially misleading".
The BBC's director general had previously apologised, saying there had been "a significant failing in relation to accuracy".
The authority has directed the broadcaster to broadcast a prime-time declaration about its conclusions.
"Since this amounts to a major infringement of our code, we are ordering the broadcaster to air a message of our conclusions against it on the BBC's second channel at 21:00, with a schedule to be finalised," the regulator stated.
'Potential to Damage Credibility'
The watchdog's report stated: "Our probe determined that the documentary's lack of disclosure that the narrator's male guardian served in a post in the Hamas-administered government was materially misleading.
"Consequently that the audience did not have vital facts which may have been extremely pertinent to their assessment of the voice and the details he provided.
"Credibility is at the heart of the bond between a media organization and its audience, especially for a public service broadcaster such as the public broadcaster.
"This failing had the potential to damage the very considerable degrees of confidence that audiences would have put in a factual film from the broadcaster about the Israel-Gaza war."
The documentary was removed from the BBC's streaming service in last February after the boy's personal associations were revealed, and in July an broadcaster's internal assessment found it infringed the corporation's journalistic standards on truthfulness.
A corporation official said: "The authority's determination is in agreement with the results of Peter Johnston's review, that there was a major oversight in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we agree with the regulator's ruling in full. We will comply with the sanction as soon as the schedule and wording are finalised."
