The BBC engaged in a "significant breach" of industry standards by failing to disclose that the presenter of a programme about the Gaza situation was the son of a Hamas representative, according to regulatory body Ofcom.
An investigation by the media regulator into the documentary titled Gaza: How to Survive a Warzone has determined that the programme was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, saying there had been "a significant failing in relation to accuracy".
The authority has directed the corporation to air a prime-time announcement about its conclusions.
"Since this amounts to a serious breach of our regulations, we are ordering the BBC to transmit a message of our determinations against it on BBC Two at nine o'clock in the evening, with a schedule to be finalised," the statement read.
'Risk to Undermine Trust'
The regulator's statement said: "Our investigation determined that the documentary's lack of disclosure that the narrator's parent occupied a role in the Hamas-controlled government was materially misleading.
"It meant that the audience did not have essential details which may have been very significant to their judgment of the voice and the details he presented.
"Credibility is at the heart of the relationship between a media organization and its viewers, notably for a state-funded media outlet such as the BBC.
"This oversight had the risk to erode the significantly high levels of trust that audiences would have put in a documentary produced by the BBC about the Israel-Gaza war."
The film was withdrawn from iPlayer in last February after the presenter's personal associations were revealed, and in the month of July an internal BBC review determined it breached the corporation's journalistic standards on truthfulness.
A BBC spokesperson stated: "The Ofcom ruling is in line with the findings of Peter Johnston's review, that there was a serious error in the programme in relation to the BBC's Editorial Guidelines on accuracy, which reflects Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we accept the regulator's ruling in its entirety. We will adhere to the sanction as soon as the schedule and wording are finalised."
