The British broadcaster engaged in a "significant breach" of broadcasting rules by omitting to mention that the narrator of a programme about Gaza was the son of a Hamas administrator, according to British broadcasting authority Ofcom.
An inquiry by Ofcom into the programme Gaza: How to Survive a Warzone has concluded that the programme was "significantly deceptive".
The BBC's director general had already issued an apology, saying there had been "a serious error in relation to accuracy".
The regulator has instructed the corporation to transmit a evening declaration about its findings.
"Given this constitutes a significant violation of our regulations, we are instructing the BBC to transmit a statement of our conclusions against it on the BBC's second channel at nine o'clock in the evening, with a schedule to be confirmed," it said.
'Potential to Undermine Credibility'
The regulator's announcement said: "The inquiry we conducted determined that the film's omission to reveal that the presenter's male guardian occupied a post in the Hamas-run administration was significantly deceptive.
"This implied that the audience did not have vital facts which may have been very significant to their evaluation of the presenter and the information he shared.
"Confidence is at the heart of the connection between a television network and its viewers, especially for a public service broadcaster such as the British Broadcasting Corporation.
"This error had the possibility to erode the significantly high amounts of credibility that the public would have placed in a BBC factual programme about the conflict in Gaza."
The programme was removed from the online platform in last February after the narrator's familial connections emerged, and in this past July an broadcaster's internal assessment found it violated the corporation's editorial guidelines on truthfulness.
A BBC spokesperson commented: "The authority's determination is in line with the results of the corporation's inquiry, that there was a significant failing in the documentary in relation to the BBC's Editorial Guidelines on factual correctness, which corresponds to Rule 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we comply with the authority's determination in full. We will follow the sanction as soon as the schedule and wording are determined."
