The public service broadcaster committed a "serious breach" of industry standards by failing to disclose that the voice of a documentary about the Gaza conflict was the child of a Hamas representative, as determined by UK media regulator Ofcom.
An probe by the media regulator into the programme Gaza: How to Survive a Warzone has found that the film was "significantly deceptive".
The chief executive of the broadcaster had previously apologised, noting there had been "a serious error in relation to accuracy".
The authority has directed the BBC to broadcast a peak-time announcement about its conclusions.
"Since this amounts to a significant violation of our code, we are directing the corporation to transmit a statement of our conclusions against it on the BBC's second channel at 9pm, with a schedule to be determined," the statement read.
'Possibility to Erode Credibility'
The watchdog's announcement stated: "The inquiry we conducted determined that the programme's lack of disclosure that the narrator's male guardian held a position in the Hamas-controlled government was materially misleading.
"Consequently that the audience did not have vital facts which may have been very significant to their judgment of the presenter and the details he shared.
"Trust is at the core of the bond between a broadcaster and its public, particularly for a national broadcasting corporation such as the public broadcaster.
"This error had the possibility to damage the significantly high levels of credibility that the public would have put in a factual film from the broadcaster about the Gaza conflict."
The film was pulled from iPlayer in last February after the presenter's family links were revealed, and in this past July an corporation's own inquiry determined it infringed the organization's editorial guidelines on factual correctness.
A representative for the broadcaster commented: "The regulator's decision is in accordance with the results of Peter Johnston's review, that there was a major oversight in the programme in relation to the BBC's Editorial Guidelines on factual correctness, which aligns with Rule 2.2 of the regulator's media standards.
"We expressed regret for this and we agree with the authority's determination in full. We will follow the penalty as soon as the date and wording are confirmed."
