The British broadcaster committed a "significant breach" of broadcasting rules by omitting to mention that the voice of a film about the Gaza conflict was the offspring of a Hamas official, as determined by British broadcasting authority Ofcom.
An probe by the media regulator into the programme Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The head of the BBC had already issued an apology, noting there had been "a serious error in relation to accuracy".
The regulator has ordered the corporation to air a peak-time declaration about its findings.
"As this represents a significant violation of our rules, we are instructing the broadcaster to air a message of our determinations against it on BBC Two at 9pm, with a schedule to be determined," it said.
'Risk to Undermine Confidence'
The authority's report said: "Our investigation concluded that the documentary's failure to disclose that the voice's male guardian held a position in the Hamas-controlled authority was substantially inaccurate.
"It meant that the audience did not have essential details which may have been very significant to their assessment of the narrator and the information he provided.
"Trust is at the heart of the bond between a broadcaster and its public, notably for a national broadcasting corporation such as the public broadcaster.
"This oversight had the risk to damage the exceptionally strong degrees of credibility that audiences would have placed in a BBC factual programme about the conflict in Gaza."
The film was pulled from the online platform in last February after the narrator's personal associations emerged, and in July an internal BBC review determined it violated the organization's journalistic standards on factual correctness.
A representative for the broadcaster said: "The Ofcom ruling is in agreement 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 truthfulness, which aligns with Rule 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we agree with Ofcom's decision in full. We will adhere to the penalty as soon as the timing and wording are finalised."
