The public service broadcaster committed a "serious breach" of industry standards by failing to disclose that the voice of a documentary about Gaza was the offspring of a Hamas official, according to regulatory body Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The BBC's director general had earlier expressed regret, saying there had been "a serious error in relation to factual correctness".
Ofcom has directed the broadcaster to broadcast a prime-time declaration about its findings.
"As this represents a significant violation of our code, we are instructing the BBC to broadcast a statement of our determinations against it on the BBC's second channel at 9pm, with a timing to be confirmed," the statement read.
'Possibility to Undermine Credibility'
The regulator's statement said: "Our probe found that the film's failure to disclose that the narrator's male guardian served in a position in the Hamas-controlled government was substantially inaccurate.
"It meant that the viewers did not have vital facts which may have been highly relevant to their assessment of the voice and the content he presented.
"Confidence is at the heart of the connection between a broadcaster and its public, especially for a public service broadcaster such as the BBC.
"This oversight had the possibility to damage the significantly high degrees of trust that viewers would have invested in a BBC factual programme about the conflict in Gaza."
The programme was pulled from the BBC's streaming service in February after the narrator's personal associations came to light, and in the month of July an broadcaster's internal assessment concluded it infringed the organization's editorial guidelines on accuracy.
A corporation official said: "The regulator's decision is in agreement with the conclusions of Peter Johnston's review, that there was a significant failing in the film in relation to the broadcaster's journalistic policies on factual correctness, which reflects Rule 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we comply with Ofcom's decision in full. We will follow the sanction as soon as the timing and wording are determined."
