The British broadcaster engaged in a "major breach" of broadcasting rules by omitting to mention that the voice of a programme about Gaza was the child of a Hamas official, according to UK media regulator Ofcom.
An probe by the broadcasting watchdog into Gaza: How to Survive a Warzone has concluded that the programme was "materially misleading".
The BBC's director general had previously apologised, stating there had been "a significant failing in relation to truthfulness".
The authority has ordered the corporation to transmit a evening declaration about its conclusions.
"Since this amounts to a major infringement of our regulations, we are directing the corporation to air a message of our conclusions against it on BBC2 at nine o'clock in the evening, with a schedule to be confirmed," the regulator stated.
'Potential to Damage Confidence'
The regulator's report said: "Our probe determined that the programme's failure to disclose that the voice's parent served in a position in the Hamas-run authority was materially misleading.
"Consequently that the audience did not have essential details which may have been very significant to their evaluation of the narrator and the information he provided.
"Credibility is at the heart of the relationship between a television network and its viewers, particularly for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the risk to erode the exceptionally strong amounts of credibility that viewers would have invested in a BBC factual programme about the Gaza conflict."
The programme was withdrawn from iPlayer in last February after the presenter's familial connections came to light, and in the month of July an broadcaster's internal assessment concluded it infringed the broadcaster's journalistic standards on accuracy.
A corporation official commented: "The Ofcom ruling is in agreement with the findings of Peter Johnston's review, that there was a major oversight in the film in relation to the BBC's Editorial Guidelines on accuracy, which corresponds to Rule 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we comply with the authority's determination in complete. We will comply with the sanction as soon as the schedule and wording are determined."
