The BBC was found to have committed a "major breach" of broadcasting rules by omitting to mention that the voice of a film about Gaza was the son of a Hamas representative, as ruled by UK media regulator Ofcom.
An inquiry by the broadcasting watchdog into the documentary titled Gaza: How to Survive a Warzone has determined that the documentary was "materially misleading".
The head of the BBC had earlier expressed regret, saying there had been "a significant failing in relation to accuracy".
Ofcom has instructed the corporation to broadcast a peak-time announcement about its conclusions.
"Given this constitutes a serious breach of our rules, we are instructing the corporation to transmit a message of our determinations against it on the BBC's second channel at 21:00, with a date to be finalised," the statement read.
'Potential to Erode Trust'
The regulator's report declared: "Our probe concluded that the film's omission to reveal that the presenter's male guardian held a post in the Hamas-controlled administration was significantly deceptive.
"Consequently that the audience did not have vital facts which may have been extremely pertinent to their judgment of the presenter and the information he presented.
"Trust is at the core of the bond between a media organization and its viewers, particularly for a public service broadcaster such as the BBC.
"This error had the possibility to damage the exceptionally strong amounts of confidence that viewers would have placed in a factual film from the broadcaster about the conflict in Gaza."
The programme was withdrawn from the BBC's streaming service in February after the narrator's family links came to light, and in this past July an corporation's own inquiry found it infringed the corporation's editorial guidelines on factual correctness.
A representative for the broadcaster said: "The regulator's decision is in accordance with the conclusions of Peter Johnston's review, that there was a major oversight in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which aligns with regulation 2.2 of the regulator's media standards.
"We issued an apology for this and we accept Ofcom's decision in its entirety. We will comply with the sanction as soon as the schedule and wording are finalised."
