The British broadcaster engaged in a "significant breach" of industry standards by failing to disclose that the voice of a programme about the Gaza situation was the offspring of a Hamas administrator, according to UK media regulator Ofcom.
An investigation by Ofcom into the documentary titled Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The BBC's director general had previously apologised, saying there had been "a major oversight in relation to factual correctness".
The regulator has instructed the broadcaster to transmit a peak-time announcement about its findings.
"As this represents a major infringement of our rules, we are ordering the BBC to transmit a statement of our determinations against it on the BBC's second channel at 21:00, with a date to be finalised," it said.
'Potential to Erode Confidence'
The authority's report said: "Our probe determined that the programme's omission to reveal that the narrator's parent served in a post in the Hamas-run administration was substantially inaccurate.
"Consequently that the viewers did not have essential details which may have been extremely pertinent to their assessment of the presenter and the information he presented.
"Confidence is at the core of the bond between a television network and its audience, particularly for a state-funded media outlet such as the public broadcaster.
"This oversight had the potential to erode the very considerable degrees of confidence that viewers would have invested in a BBC factual programme about the conflict in Gaza."
The programme was removed from iPlayer in February after the boy's personal associations were revealed, and in the month of July an internal BBC review found it breached the corporation's editorial guidelines on accuracy.
A representative for the broadcaster commented: "The regulator's decision is in line with the conclusions of the internal assessment, that there was a major oversight in the film in relation to the BBC's Editorial Guidelines on factual correctness, which corresponds to clause 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with the authority's determination in complete. We will adhere to the penalty as soon as the date and wording are confirmed."
