The public service broadcaster engaged in a "significant breach" of broadcasting rules by omitting to mention that the narrator of a film about the Gaza situation was the offspring 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 programme was "substantially inaccurate".
The head of the BBC had earlier expressed regret, noting there had been "a significant failing in relation to accuracy".
The authority has instructed the BBC to air a evening declaration about its findings.
"As this represents a significant violation of our code, we are directing the corporation to broadcast a statement of our findings against it on BBC Two at nine o'clock in the evening, with a timing to be confirmed," the statement read.
'Possibility to Undermine Trust'
The authority's announcement said: "The inquiry we conducted determined that the documentary's lack of disclosure that the presenter's parent occupied a role in the Hamas-run administration was materially misleading.
"It meant that the viewers did not have critical information which may have been extremely pertinent to their evaluation of the voice and the information he presented.
"Confidence is at the core of the relationship between a media organization and its public, particularly for a national broadcasting corporation such as the British Broadcasting Corporation.
"This error had the potential to erode the very considerable degrees of confidence that viewers would have put in a factual film from the broadcaster about the conflict in Gaza."
The film was removed from the BBC's streaming service in last February after the narrator's family links were revealed, and in this past July an internal BBC review concluded it breached the broadcaster's journalistic standards on truthfulness.
A BBC spokesperson commented: "The Ofcom ruling is in agreement with the conclusions of the internal assessment, that there was a significant failing in the documentary in relation to the corporation's content standards on accuracy, which reflects Rule 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we accept Ofcom's decision in full. We will follow the sanction as soon as the timing and wording are determined."
