The BBC committed a "major breach" of media regulations by failing to disclose that the voice of a documentary about the Gaza situation was the son of a Hamas administrator, as ruled by UK media regulator Ofcom.
An investigation by Ofcom into the programme Gaza: How to Survive a Warzone has determined that the documentary was "substantially inaccurate".
The BBC's director general had already issued an apology, saying there had been "a serious error in relation to truthfulness".
The authority has instructed the BBC to transmit a prime-time declaration about its conclusions.
"Since this amounts to a significant violation of our rules, we are instructing the broadcaster to air a message of our findings against it on BBC2 at 21:00, with a timing to be confirmed," it said.
'Possibility to Erode Confidence'
The watchdog's report declared: "Our probe determined that the film's lack of disclosure that the presenter's male guardian occupied a position in the Hamas-administered administration was materially misleading.
"It meant that the viewers did not have critical information which may have been extremely pertinent to their judgment of the presenter and the details he shared.
"Trust is at the core of the relationship between a media organization and its viewers, especially for a public service broadcaster such as the British Broadcasting Corporation.
"This failing had the risk to damage the exceptionally strong amounts of trust that the public would have invested in a documentary produced by the BBC about the conflict in Gaza."
The programme was withdrawn from the online platform in last February after the presenter's familial connections were revealed, and in July an broadcaster's internal assessment found it breached the broadcaster's journalistic standards on truthfulness.
A representative for the broadcaster stated: "The regulator's decision is in agreement with the findings of the internal assessment, that there was a significant failing in the film in relation to the BBC's Editorial Guidelines on accuracy, which reflects regulation 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we accept the regulator's ruling in its entirety. We will adhere to the directive as soon as the date and wording are determined."
