The British broadcaster committed a "significant breach" of industry standards by not revealing that the voice of a film about Gaza was the son of a Hamas official, as ruled by UK media regulator Ofcom.
An investigation by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The BBC's director general had previously apologised, noting there had been "a significant failing in relation to truthfulness".
Ofcom has ordered the broadcaster to transmit a evening declaration about its decisions.
"As this represents a major infringement of our regulations, we are instructing the BBC to transmit a message of our conclusions against it on BBC Two at 21:00, with a schedule to be determined," the regulator stated.
'Risk to Erode Trust'
The authority's statement stated: "Our investigation concluded that the documentary's lack of disclosure that the presenter's father held a position in the Hamas-administered administration was materially misleading.
"Consequently that the audience did not have critical information which may have been highly relevant to their judgment of the narrator and the information he presented.
"Trust is at the heart of the bond between a media organization and its audience, especially for a national broadcasting corporation such as the public broadcaster.
"This error had the risk to undermine the very considerable amounts of trust that audiences would have put in a BBC factual programme about the conflict in Gaza."
The film was withdrawn from iPlayer in February after the narrator's familial connections came to light, and in July an internal BBC review found it infringed the broadcaster's journalistic standards on truthfulness.
A corporation official stated: "The Ofcom ruling is in line with the conclusions of Peter Johnston's review, that there was a serious error in the film in relation to the BBC's Editorial Guidelines on factual correctness, which reflects regulation 2.2 of the regulator's media standards.
"We have apologised for this and we accept the authority's determination in full. We will follow the directive as soon as the timing and language are finalised."
