The BBC engaged in a "major breach" of media regulations by omitting to mention that the narrator of a film about the Gaza conflict was the child of a Hamas representative, as ruled by British broadcasting authority Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has found that the documentary was "significantly deceptive".
The head of the BBC had earlier expressed regret, stating there had been "a serious error in relation to factual correctness".
The authority has instructed the corporation to air a evening declaration about its conclusions.
"Given this constitutes a serious breach of our rules, we are instructing the broadcaster to broadcast a announcement of our findings against it on the BBC's second channel at nine o'clock in the evening, with a date to be confirmed," the regulator stated.
'Possibility to Damage Trust'
The authority's announcement said: "The inquiry we conducted concluded that the documentary's failure to disclose that the narrator's male guardian held a post in the Hamas-run government was materially misleading.
"It meant that the viewers did not have vital facts which may have been extremely pertinent to their assessment of the voice and the information he presented.
"Trust is at the heart of the relationship between a media organization and its public, notably for a public service broadcaster such as the BBC.
"This error had the potential to undermine the very considerable amounts of credibility that the public would have invested in a factual film from the broadcaster about the conflict in Gaza."
The programme was removed from the online platform in last February after the presenter's family links came to light, and in the month of July an broadcaster's internal assessment determined it violated the organization's editorial guidelines on truthfulness.
A representative for the broadcaster said: "The Ofcom ruling is in line with the findings of the corporation's inquiry, that there was a major oversight in the documentary in relation to the broadcaster's journalistic policies on truthfulness, which reflects regulation 2.2 of the regulator's media standards.
"We have apologised for this and we agree with the authority's determination in full. We will adhere to the sanction as soon as the date and language are determined."
