The BBC committed a "serious breach" of media regulations by not revealing that the voice of a programme about Gaza was the son of a Hamas official, as ruled by regulatory body Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has concluded that the documentary was "materially misleading".
The head of the BBC had already issued an apology, stating there had been "a major oversight in relation to accuracy".
Ofcom has ordered the corporation to broadcast a peak-time announcement about its decisions.
"Given this constitutes a serious breach of our regulations, we are directing the broadcaster to air a statement of our conclusions against it on the BBC's second channel at 9pm, with a timing to be determined," the regulator stated.
'Risk to Undermine Confidence'
The regulator's announcement stated: "Our probe found that the programme's failure to disclose that the narrator's parent occupied a role in the Hamas-controlled authority was materially misleading.
"This implied that the audience did not have critical information which may have been extremely pertinent to their evaluation of the presenter and the information he shared.
"Trust is at the center of the connection between a media organization and its viewers, notably for a public service broadcaster such as the public broadcaster.
"This oversight had the potential to undermine the exceptionally strong amounts of credibility that viewers would have placed in a factual film from the broadcaster about the conflict in Gaza."
The film was removed from the online platform in last February after the narrator's family links came to light, and in July an corporation's own inquiry concluded it violated the organization's editorial guidelines on accuracy.
A corporation official stated: "The regulator's decision is in agreement with the results of the internal assessment, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on factual correctness, which corresponds to clause 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 penalty as soon as the date and wording are confirmed."
