The BBC engaged in a "serious breach" of media regulations by omitting to mention that the voice of a documentary about the Gaza conflict was the son of a Hamas administrator, according to British broadcasting authority Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has determined that the programme was "substantially inaccurate".
The chief executive of the broadcaster had already issued an apology, saying there had been "a serious error in relation to truthfulness".
The authority has instructed the broadcaster to air a prime-time announcement about its findings.
"Since this amounts to a major infringement of our rules, we are instructing the corporation to air a statement of our findings against it on the BBC's second channel at 21:00, with a date to be determined," the statement read.
'Risk to Damage Trust'
The watchdog's report said: "Our probe found that the film's lack of disclosure that the voice's parent occupied a position in the Hamas-run authority was significantly deceptive.
"It meant that the public did not have vital facts which may have been extremely pertinent to their evaluation of the voice and the content he presented.
"Trust is at the core of the connection between a broadcaster and its audience, notably for a national broadcasting corporation such as the BBC.
"This oversight had the possibility to erode the significantly high amounts of credibility that the public would have invested in a BBC factual programme about the Gaza conflict."
The programme was pulled from the online platform in last February after the boy's personal associations were revealed, and in July an broadcaster's internal assessment found it infringed the corporation's journalistic standards on truthfulness.
A corporation official commented: "The Ofcom ruling is in accordance with the conclusions of the corporation's inquiry, that there was a serious error in the film in relation to the corporation's content standards on accuracy, which reflects Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we accept the regulator's ruling in full. We will follow the penalty as soon as the schedule and wording are confirmed."
