The public service broadcaster was found to have committed a "major breach" of media regulations by not revealing that the narrator of a programme about the Gaza situation was the child of a Hamas official, as determined by regulatory body Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The head of the BBC had earlier expressed regret, noting there had been "a major oversight in relation to accuracy".
The authority has directed the broadcaster to transmit a prime-time declaration about its findings.
"As this represents a serious breach of our code, we are directing the broadcaster to broadcast a message of our conclusions against it on BBC Two at 9pm, with a timing to be finalised," the regulator stated.
'Possibility to Damage Credibility'
The regulator's report said: "The inquiry we conducted determined that the programme's omission to reveal that the voice's male guardian served in a role in the Hamas-run authority was substantially inaccurate.
"It meant that the viewers did not have critical information which may have been very significant to their assessment of the presenter and the details he shared.
"Credibility is at the heart of the bond between a broadcaster and its audience, especially for a state-funded media outlet such as the BBC.
"This failing had the possibility to damage the very considerable levels of confidence that the public would have placed in a factual film from the broadcaster about the Gaza conflict."
The programme was pulled from the online platform in last February after the boy's personal associations came to light, and in July an internal BBC review found it breached the corporation's journalistic standards on truthfulness.
A corporation official commented: "The regulator's decision is in agreement with the conclusions of the corporation's inquiry, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on accuracy, which corresponds to regulation 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we accept the regulator's ruling in full. We will adhere to the sanction as soon as the schedule and wording are determined."
