The public service broadcaster was found to have committed a "serious breach" of broadcasting rules by omitting to mention that the narrator of a documentary about the Gaza situation was the child of a Hamas official, according to UK media regulator Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has concluded that the programme was "substantially inaccurate".
The chief executive of the broadcaster had earlier expressed regret, saying there had been "a significant failing in relation to accuracy".
The regulator has ordered the corporation to broadcast a prime-time declaration about its decisions.
"As this represents a major infringement of our code, we are ordering the broadcaster to air a message of our findings against it on BBC Two at 9pm, with a timing to be confirmed," it said.
'Possibility to Undermine Trust'
The authority's report said: "Our investigation concluded that the documentary's failure to disclose that the voice's male guardian occupied a position in the Hamas-run administration was substantially inaccurate.
"This implied that the viewers did not have essential details which may have been very significant to their judgment of the voice and the details he presented.
"Credibility is at the core of the relationship between a media organization and its audience, particularly for a public service broadcaster such as the BBC.
"This oversight had the potential to erode the significantly high degrees of credibility that audiences would have invested in a documentary produced by the BBC about the conflict in Gaza."
The documentary was pulled from iPlayer in last February after the narrator's family links emerged, and in July an internal BBC review determined it violated the organization's editorial guidelines on accuracy.
A representative for the broadcaster said: "The Ofcom ruling is in line with the conclusions of the internal assessment, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on truthfulness, which reflects Rule 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we accept Ofcom's decision in full. We will comply with the penalty as soon as the timing and wording are determined."
