The British broadcaster engaged in a "serious breach" of industry standards by omitting to mention that the narrator of a documentary about Gaza was the offspring of a Hamas official, as determined by UK media regulator Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The head of the BBC had earlier expressed regret, saying there had been "a significant failing in relation to truthfulness".
The regulator has instructed the corporation to broadcast a peak-time statement about its conclusions.
"Given this constitutes a serious breach of our code, we are directing the corporation to air a statement of our conclusions against it on BBC Two at nine o'clock in the evening, with a timing to be determined," the statement read.
'Risk to Erode Confidence'
The regulator's report said: "Our investigation found that the programme's omission to reveal that the voice's father held a post in the Hamas-administered administration was substantially inaccurate.
"This implied that the public did not have essential details which may have been very significant to their evaluation of the presenter and the details he provided.
"Credibility is at the center of the relationship between a media organization and its viewers, particularly for a public service broadcaster such as the public broadcaster.
"This error had the possibility to undermine the significantly high levels of confidence that the public would have placed in a documentary produced by the BBC about the Gaza conflict."
The documentary was removed from iPlayer in the month of February after the presenter's personal associations came to light, and in July an broadcaster's internal assessment determined it infringed the corporation's journalistic standards on factual correctness.
A representative for the broadcaster stated: "The authority's determination is in accordance with the results of Peter Johnston's review, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on truthfulness, which reflects regulation 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we comply with the regulator's ruling in complete. We will follow the directive as soon as the schedule and language are confirmed."
