The British broadcaster engaged in a "serious breach" of media regulations by omitting to mention that the narrator of a programme about the Gaza situation was the son of a Hamas official, according to British broadcasting authority Ofcom.
An inquiry by the media regulator into Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The BBC's director general had already issued an apology, stating there had been "a serious error in relation to factual correctness".
Ofcom has instructed the broadcaster to air a prime-time announcement about its findings.
"As this represents a significant violation of our code, we are directing the corporation to air a statement of our conclusions against it on BBC2 at 21:00, with a schedule to be confirmed," it said.
'Potential to Damage Trust'
The authority's announcement declared: "Our probe determined that the documentary's omission to reveal that the presenter's male guardian served in a post in the Hamas-administered administration was materially misleading.
"Consequently that the audience did not have vital facts which may have been extremely pertinent to their evaluation of the presenter and the details he provided.
"Credibility is at the heart of the relationship between a television network and its audience, especially for a national broadcasting corporation such as the public broadcaster.
"This oversight had the potential to erode the significantly high levels of credibility that the public would have put in a factual film from the broadcaster about the Israel-Gaza war."
The programme was withdrawn from iPlayer in the month of February after the boy's personal associations emerged, and in this past July an corporation's own inquiry found it infringed the organization's journalistic standards on accuracy.
A representative for the broadcaster said: "The Ofcom ruling is in line with the findings of the internal assessment, that there was a serious error in the film in relation to the corporation's content standards on accuracy, which corresponds to regulation 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept Ofcom's decision in its entirety. We will comply with the penalty as soon as the schedule and language are determined."
