The BBC was found to have committed a "significant breach" of media regulations by omitting to mention that the presenter of a programme about the Gaza conflict was the son of a Hamas official, as ruled by regulatory body Ofcom.
An investigation by Ofcom into the programme Gaza: How to Survive a Warzone has determined that the film was "materially misleading".
The chief executive of the broadcaster had already issued an apology, saying there had been "a serious error in relation to factual correctness".
The regulator has directed the BBC to transmit a prime-time declaration about its findings.
"As this represents a major infringement of our code, we are instructing the corporation to air a statement of our conclusions against it on BBC2 at 21:00, with a schedule to be determined," it said.
'Potential to Undermine Credibility'
The regulator's statement stated: "Our probe concluded that the film's failure to disclose that the voice's father held a role in the Hamas-administered administration was substantially inaccurate.
"This implied that the viewers did not have vital facts which may have been extremely pertinent to their assessment of the voice and the details he presented.
"Confidence is at the heart of the relationship between a broadcaster and its audience, notably for a national broadcasting corporation such as the public broadcaster.
"This failing had the potential to erode the significantly high levels of credibility that audiences would have put in a factual film from the broadcaster about the Israel-Gaza war."
The documentary was pulled from iPlayer in last February after the presenter's familial connections emerged, and in this past July an corporation's own inquiry found it violated the organization's journalistic standards on factual correctness.
A representative for the broadcaster stated: "The regulator's decision is in line with the findings of Peter Johnston's review, that there was a serious error in the film in relation to the broadcaster's journalistic policies on accuracy, which corresponds to Rule 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we agree with Ofcom's decision in complete. We will adhere to the sanction as soon as the timing and wording are finalised."
