The BBC committed a "serious breach" of media regulations by failing to disclose that the narrator of a documentary about the Gaza conflict was the offspring of a Hamas administrator, as ruled by UK media regulator Ofcom.
An probe by Ofcom into the programme Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The BBC's director general had earlier expressed regret, stating there had been "a significant failing in relation to accuracy".
The regulator has directed the BBC to air a evening declaration about its findings.
"Since this amounts to a serious breach of our code, we are directing the corporation to air a announcement of our findings against it on the BBC's second channel at 21:00, with a schedule to be determined," the regulator stated.
'Possibility to Undermine Credibility'
The regulator's report said: "The inquiry we conducted concluded that the programme's lack of disclosure that the presenter's parent served in a post in the Hamas-controlled administration was materially misleading.
"Consequently that the audience did not have vital facts which may have been extremely pertinent to their assessment of the narrator and the information he presented.
"Credibility is at the core of the connection between a media organization and its viewers, notably for a state-funded media outlet such as the BBC.
"This error had the potential to damage the exceptionally strong levels of credibility that audiences would have invested in a factual film from the broadcaster about the Gaza conflict."
The film was withdrawn from the BBC's streaming service in the month of February after the boy's family links emerged, and in this past July an internal BBC review concluded it breached the broadcaster's editorial guidelines on accuracy.
A BBC spokesperson commented: "The regulator's decision is in agreement with the conclusions of Peter Johnston's review, that there was a significant failing in the programme in relation to the broadcaster's journalistic policies on accuracy, which reflects Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we comply with the authority's determination in its entirety. We will follow the sanction as soon as the date and wording are determined."