The BBC committed a "significant breach" of broadcasting rules by omitting to mention that the narrator of a film about Gaza was the child of a Hamas official, as determined by UK media regulator Ofcom.
An probe by the media regulator into the programme Gaza: How to Survive a Warzone has determined that the documentary was "substantially inaccurate".
The chief executive of the broadcaster had previously apologised, stating there had been "a serious error in relation to accuracy".
Ofcom has directed the broadcaster to air a evening declaration about its findings.
"Given this constitutes a serious breach of our regulations, we are directing the BBC to transmit a message of our determinations against it on BBC2 at 21:00, with a date to be confirmed," the statement read.
'Potential to Erode Confidence'
The authority's report declared: "Our probe concluded that the documentary's lack of disclosure that the voice's male guardian occupied a position in the Hamas-controlled administration was substantially inaccurate.
"Consequently that the public did not have critical information which may have been highly relevant to their judgment of the narrator and the content he provided.
"Credibility is at the core of the bond between a media organization and its viewers, particularly for a public service broadcaster such as the public broadcaster.
"This oversight had the potential to erode the exceptionally strong degrees of trust that the public would have invested in a documentary produced by the BBC about the Israel-Gaza war."
The documentary was pulled from the online platform in February after the boy's familial connections emerged, and in July an internal BBC review concluded it violated the broadcaster's journalistic standards on truthfulness.
A BBC spokesperson said: "The regulator's decision is in accordance with the results of the corporation's inquiry, that there was a significant failing in the film in relation to the BBC's Editorial Guidelines on truthfulness, which reflects regulation 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we accept the regulator's ruling in its entirety. We will adhere to the sanction as soon as the schedule and language are determined."
