The BBC was found to have committed a "serious breach" of broadcasting rules by failing to disclose that the narrator of a programme about the Gaza conflict was the son of a Hamas administrator, according to British broadcasting authority Ofcom.
An probe by Ofcom into the programme Gaza: How to Survive a Warzone has determined that the film was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a significant failing in relation to accuracy".
The authority has directed the corporation to transmit a prime-time declaration about its findings.
"As this represents a significant violation of our code, we are instructing the broadcaster to air a message of our determinations against it on BBC Two at 9pm, with a timing to be confirmed," the regulator stated.
'Potential to Erode Trust'
The watchdog's report said: "Our probe found that the programme's lack of disclosure that the presenter's parent served in a role in the Hamas-controlled administration was significantly deceptive.
"It meant that the viewers did not have essential details which may have been extremely pertinent to their judgment of the voice and the information he presented.
"Trust is at the core of the connection between a media organization and its viewers, especially for a national broadcasting corporation such as the public broadcaster.
"This failing had the potential to erode the significantly high levels of credibility that the public would have put in a documentary produced by the BBC about the Israel-Gaza war."
The film was withdrawn from the BBC's streaming service in last February after the narrator's personal associations were revealed, and in the month of July an corporation's own inquiry concluded it breached the corporation's journalistic standards on accuracy.
A representative for the broadcaster said: "The Ofcom ruling is in accordance with the findings of the corporation's inquiry, that there was a serious error in the documentary in relation to the broadcaster's journalistic policies on accuracy, which corresponds to clause 2.2 of the regulator's media standards.
"We issued an apology for this and we comply with the regulator's ruling in full. We will follow the directive as soon as the date and wording are confirmed."
