The public service broadcaster engaged in a "serious breach" of industry standards by not revealing that the narrator of a programme about the Gaza situation was the offspring of a Hamas official, according to regulatory body Ofcom.
An probe by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has concluded that the film was "materially misleading".
The BBC's director general had previously apologised, saying there had been "a serious error in relation to factual correctness".
The authority has instructed the broadcaster to broadcast a prime-time declaration about its findings.
"As this represents a significant violation of our regulations, we are directing the BBC to air a message of our determinations against it on the BBC's second channel at 9pm, with a date to be finalised," the statement read.
'Risk to Erode Trust'
The authority's report stated: "The inquiry we conducted found that the documentary's omission to reveal that the presenter's father occupied a role in the Hamas-administered government was materially misleading.
"It meant that the public did not have vital facts which may have been extremely pertinent to their judgment of the voice and the details he presented.
"Confidence is at the heart of the relationship between a television network and its audience, particularly for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the potential to undermine the exceptionally strong amounts of trust that audiences would have invested in a factual film from the broadcaster about the Israel-Gaza war."
The film was withdrawn from the online platform in last February after the presenter's family links were revealed, and in July an corporation's own inquiry determined it infringed the organization's journalistic standards on factual correctness.
A BBC spokesperson commented: "The Ofcom ruling is in line with the conclusions of the internal assessment, that there was a serious error in the documentary in relation to the broadcaster's journalistic policies on accuracy, which reflects Rule 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept the regulator's ruling in full. We will adhere to the sanction as soon as the timing and language are confirmed."
