The BBC committed a "serious breach" of industry standards by not revealing that the presenter of a documentary about the Gaza situation was the son of a Hamas official, as determined by UK media regulator Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has determined that the documentary was "materially misleading".
The head of the BBC had already issued an apology, stating there had been "a serious error in relation to accuracy".
The regulator has instructed the BBC to broadcast a prime-time statement about its conclusions.
"Given this constitutes a significant violation of our code, we are ordering the corporation to transmit a message of our conclusions against it on BBC2 at nine o'clock in the evening, with a timing to be determined," the regulator stated.
'Potential to Erode Confidence'
The watchdog's statement stated: "Our probe determined that the documentary's omission to reveal that the narrator's male guardian occupied a role in the Hamas-controlled government was materially misleading.
"Consequently that the public did not have critical information which may have been highly relevant to their judgment of the voice and the details he provided.
"Credibility is at the heart of the bond between a broadcaster and its public, especially for a state-funded media outlet such as the BBC.
"This failing had the possibility to undermine the significantly high degrees of credibility that viewers would have invested in a factual film from the broadcaster about the Gaza conflict."
The programme was pulled from the online platform in February after the narrator's family links came to light, and in July an corporation's own inquiry found it violated the broadcaster's editorial guidelines on factual correctness.
A representative for the broadcaster said: "The authority's determination is in line with the findings of Peter Johnston's review, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on accuracy, which reflects clause 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we accept the authority's determination in full. We will adhere to the directive as soon as the timing and language are finalised."
