The public service broadcaster engaged in a "serious breach" of industry standards by failing to disclose that the voice of a programme about the Gaza conflict was the offspring of a Hamas official, as determined by regulatory body Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The BBC's director general had earlier expressed regret, stating there had been "a serious error in relation to accuracy".
The regulator has ordered the BBC to broadcast a peak-time declaration about its findings.
"Since this amounts to a serious breach of our regulations, we are directing the BBC to air a announcement of our findings against it on BBC Two at 21:00, with a schedule to be confirmed," the statement read.
'Potential to Undermine Confidence'
The authority's report declared: "Our investigation found that the programme's omission to reveal that the voice's male guardian occupied a post in the Hamas-controlled authority was substantially inaccurate.
"This implied that the audience did not have critical information which may have been highly relevant to their judgment of the voice and the information he provided.
"Trust is at the center of the connection between a television network and its public, particularly for a public service broadcaster such as the BBC.
"This failing had the possibility to damage the very considerable levels of trust that audiences would have placed in a BBC factual programme about the conflict in Gaza."
The programme was removed from the online platform in February after the narrator's personal associations emerged, and in this past July an corporation's own inquiry found it infringed the organization's content policies on truthfulness.
A representative for the broadcaster said: "The Ofcom ruling is in accordance with the results of Peter Johnston's review, that there was a major oversight in the documentary in relation to the broadcaster's journalistic policies on truthfulness, which reflects clause 2.2 of the regulator's media standards.
"We issued an apology for this and we agree with the regulator's ruling in its entirety. We will follow the directive as soon as the date and wording are confirmed."
