The BBC was found to have committed a "major breach" of media regulations by not revealing that the presenter of a documentary about the Gaza situation was the offspring of a Hamas representative, as ruled by UK media regulator Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has found that the film was "significantly deceptive".
The head of the BBC had previously apologised, stating there had been "a serious error in relation to factual correctness".
The regulator has instructed the BBC to air a evening statement about its findings.
"As this represents a significant violation of our code, we are directing the BBC to air a announcement of our determinations against it on the BBC's second channel at 21:00, with a timing to be finalised," the statement read.
'Risk to Erode Trust'
The watchdog's announcement stated: "The inquiry we conducted concluded that the film's omission to reveal that the narrator's parent occupied a role in the Hamas-controlled administration was materially misleading.
"Consequently that the public did not have vital facts which may have been very significant to their assessment of the presenter and the information he provided.
"Trust is at the center of the bond between a television network and its public, particularly for a national broadcasting corporation such as the public broadcaster.
"This error had the possibility to damage the exceptionally strong levels of credibility that the public would have placed in a documentary produced by the BBC about the conflict in Gaza."
The programme was removed from iPlayer in February after the narrator's family links were revealed, and in the month of July an internal BBC review found it infringed the corporation's journalistic standards on truthfulness.
A BBC spokesperson commented: "The Ofcom ruling is in agreement with the results of Peter Johnston's review, that there was a major oversight in the programme in relation to the broadcaster's journalistic policies on factual correctness, which aligns with Rule 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we agree with the authority's determination in its entirety. We will follow the penalty as soon as the timing and language are finalised."
