The BBC engaged in a "major breach" of media regulations by not revealing that the presenter of a film about the Gaza conflict was the offspring of a Hamas administrator, according to UK media regulator Ofcom.
An inquiry by the broadcasting watchdog into Gaza: How to Survive a Warzone has determined that the documentary was "materially misleading".
The BBC's director general had already issued an apology, noting there had been "a significant failing in relation to accuracy".
The authority has ordered the broadcaster to transmit a prime-time announcement about its decisions.
"As this represents a significant violation of our regulations, we are instructing the broadcaster to transmit a message of our determinations against it on the BBC's second channel at 9pm, with a timing to be confirmed," the statement read.
'Risk to Erode Trust'
The watchdog's announcement declared: "Our probe determined that the documentary's failure to disclose that the voice's parent served in a position in the Hamas-run administration was significantly deceptive.
"This implied that the audience did not have essential details which may have been very significant to their evaluation of the presenter and the content he presented.
"Confidence is at the heart of the bond between a broadcaster and its audience, especially for a public service broadcaster such as the BBC.
"This failing had the risk to erode the exceptionally strong amounts of trust that the public would have invested in a BBC factual programme about the conflict in Gaza."
The programme was removed from the BBC's streaming service in February after the narrator's family links emerged, and in July an broadcaster's internal assessment found it breached the organization's journalistic standards on truthfulness.
A corporation official stated: "The authority's determination is in line with the conclusions of the corporation's inquiry, that there was a significant failing in the film in relation to the broadcaster's journalistic policies on accuracy, which corresponds to clause 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with the regulator's ruling in full. We will comply with the sanction as soon as the date and wording are finalised."
