The BBC was found to have committed a "significant breach" of media regulations by not revealing that the narrator of a film about Gaza was the son of a Hamas official, according to regulatory body Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has determined that the film was "materially misleading".
The chief executive of the broadcaster had previously apologised, noting there had been "a serious error in relation to truthfulness".
The regulator has directed the BBC to transmit a prime-time declaration about its conclusions.
"Given this constitutes a serious breach of our code, we are ordering the BBC to air a announcement of our findings against it on the BBC's second channel at 9pm, with a date to be determined," the statement read.
'Risk to Damage Credibility'
The regulator's report declared: "The inquiry we conducted concluded that the programme's omission to reveal that the voice's parent served in a post in the Hamas-controlled administration was substantially inaccurate.
"Consequently that the public did not have essential details which may have been extremely pertinent to their evaluation of the presenter and the details he presented.
"Credibility is at the heart of the connection between a broadcaster and its audience, particularly for a public service broadcaster such as the BBC.
"This failing had the possibility to damage the significantly high levels of confidence that viewers would have placed in a BBC factual programme about the Israel-Gaza war."
The programme was removed from iPlayer in February after the narrator's family links came to light, and in this past July an corporation's own inquiry determined it breached the corporation's journalistic standards on truthfulness.
A corporation official commented: "The regulator's decision is in accordance with the results of Peter Johnston's review, that there was a serious error in the documentary in relation to the corporation's content standards on truthfulness, which reflects Rule 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with the authority's determination in complete. We will comply with the sanction as soon as the date and language are finalised."
