The BBC engaged in a "major breach" of industry standards by not revealing that the voice of a film about the Gaza conflict was the child of a Hamas official, according to UK media regulator Ofcom.
An investigation by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has determined that the programme was "significantly deceptive".
The head of the BBC had earlier expressed regret, saying there had been "a serious error in relation to accuracy".
Ofcom has instructed the broadcaster to broadcast a evening declaration about its conclusions.
"Since this amounts to a major infringement of our rules, we are ordering the BBC to broadcast a message of our conclusions against it on BBC Two at 9pm, with a date to be confirmed," the statement read.
'Potential to Erode Trust'
The regulator's announcement said: "Our probe determined that the documentary's lack of disclosure that the presenter's father held a post in the Hamas-administered government was materially misleading.
"This implied that the audience did not have critical information which may have been very significant to their evaluation of the narrator and the information he presented.
"Confidence is at the heart of the connection between a media organization and its viewers, especially for a public service broadcaster such as the British Broadcasting Corporation.
"This error had the risk to damage the very considerable degrees of trust that the public would have placed in a factual film from the broadcaster about the Israel-Gaza war."
The film was pulled from the online platform in last February after the presenter's familial connections came to light, and in July an corporation's own inquiry found it breached the broadcaster's content policies on truthfulness.
A corporation official commented: "The Ofcom ruling is in agreement with the findings of the internal assessment, that there was a major oversight in the programme in relation to the BBC's Editorial Guidelines on accuracy, which aligns with Rule 2.2 of the regulator's media standards.
"We expressed regret for this and we accept the authority's determination in complete. We will follow the penalty as soon as the date and wording are finalised."
