The BBC engaged in a "significant breach" of industry standards by failing to disclose that the voice of a documentary about the Gaza situation was the son of a Hamas representative, as determined by UK media regulator Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has concluded that the film was "materially misleading".
The head of the BBC had previously apologised, saying there had been "a major oversight in relation to accuracy".
The authority has ordered the corporation to transmit a peak-time statement about its conclusions.
"As this represents a significant violation of our code, we are instructing the broadcaster to air a announcement of our determinations against it on BBC2 at nine o'clock in the evening, with a timing to be finalised," the regulator stated.
'Risk to Erode Credibility'
The authority's announcement said: "Our probe found that the programme's failure to disclose that the narrator's parent held a position in the Hamas-administered administration was materially misleading.
"It meant that the audience did not have critical information which may have been very significant to their judgment of the voice and the details he presented.
"Confidence is at the heart of the bond between a media organization and its audience, notably for a national broadcasting corporation such as the British Broadcasting Corporation.
"This failing had the risk to undermine the significantly high degrees of credibility that viewers would have invested in a factual film from the broadcaster about the Israel-Gaza war."
The documentary was pulled from the BBC's streaming service in last February after the presenter's personal associations came to light, and in this past July an broadcaster's internal assessment concluded it infringed the organization's content policies on accuracy.
A representative for the broadcaster said: "The regulator's decision is in agreement 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 factual correctness, which corresponds to Rule 2.2 of the regulator's media standards.
"We have apologised for this and we agree with Ofcom's decision in complete. We will comply with the sanction as soon as the timing and wording are determined."
