The BBC was found to have committed a "serious breach" of broadcasting rules by failing to disclose that the voice of a documentary about Gaza was the offspring of a Hamas official, as ruled by British broadcasting authority Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The chief executive of the broadcaster had previously apologised, noting there had been "a serious error in relation to truthfulness".
Ofcom has directed the BBC to broadcast a evening statement about its decisions.
"Since this amounts to a serious breach of our code, we are instructing the broadcaster to transmit a message of our findings against it on BBC2 at nine o'clock in the evening, with a date to be determined," the statement read.
'Possibility to Undermine Confidence'
The authority's statement declared: "The inquiry we conducted found that the film's lack of disclosure that the narrator's male guardian occupied a position in the Hamas-run administration was significantly deceptive.
"It meant that the public did not have critical information which may have been very significant to their judgment of the presenter and the details he presented.
"Confidence is at the heart of the relationship between a television network and its viewers, particularly for a public service broadcaster such as the British Broadcasting Corporation.
"This oversight had the possibility to damage the very considerable degrees of confidence that the public would have invested in a BBC factual programme about the conflict in Gaza."
The documentary was removed from the BBC's streaming service in February after the presenter's family links emerged, and in the month of July an internal BBC review determined it breached the corporation's editorial guidelines on accuracy.
A representative for the broadcaster said: "The regulator's decision is in line with the results of Peter Johnston's review, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on accuracy, which aligns with Rule 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we comply with the regulator's ruling in its entirety. We will comply with the sanction as soon as the timing and wording are determined."
