The British broadcaster was found to have committed a "serious breach" of broadcasting rules by failing to disclose that the narrator of a programme about the Gaza conflict was the offspring of a Hamas representative, as determined by British broadcasting authority Ofcom.
An probe by the media regulator into the documentary titled Gaza: How to Survive a Warzone has determined that the film was "significantly deceptive".
The BBC's director general had earlier expressed regret, noting there had been "a serious error in relation to factual correctness".
The regulator has directed the broadcaster to transmit a prime-time statement about its decisions.
"Since this amounts to a serious breach of our code, we are instructing the broadcaster to broadcast a announcement of our determinations against it on BBC2 at 21:00, with a date to be confirmed," the statement read.
'Risk to Erode Trust'
The authority's statement declared: "Our investigation found that the documentary's omission to reveal that the voice's father occupied a position in the Hamas-controlled government was materially misleading.
"This implied that the viewers did not have critical information which may have been highly relevant to their assessment of the presenter and the details he presented.
"Credibility is at the core of the relationship between a media organization and its viewers, especially 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 audiences would have placed in a documentary produced by the BBC about the Israel-Gaza war."
The documentary was removed from iPlayer in last February after the presenter's family links were revealed, and in this past July an broadcaster's internal assessment determined it violated the broadcaster's journalistic standards on truthfulness.
A BBC spokesperson commented: "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 corresponds to clause 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we comply with the regulator's ruling in full. We will comply with the penalty as soon as the date and wording are confirmed."
