The BBC engaged in a "major breach" of media regulations by omitting to mention that the voice of a programme about the Gaza situation was the child of a Hamas official, according to UK media regulator Ofcom.
An investigation by Ofcom into the programme Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a significant failing in relation to factual correctness".
The regulator has ordered the BBC to air a peak-time declaration about its findings.
"As this represents a major infringement of our regulations, we are ordering the broadcaster to transmit a message of our findings against it on BBC Two at 9pm, with a schedule to be confirmed," it said.
'Risk to Undermine Confidence'
The authority's report stated: "Our probe found that the film's omission to reveal that the narrator's parent held a position in the Hamas-run government was substantially inaccurate.
"Consequently that the viewers did not have essential details which may have been highly relevant to their assessment of the narrator and the information he provided.
"Credibility is at the core of the bond between a media organization and its viewers, particularly for a public service broadcaster such as the British Broadcasting Corporation.
"This failing had the possibility to damage the exceptionally strong levels of confidence that the public would have placed in a BBC factual programme about the Israel-Gaza war."
The documentary was pulled from iPlayer in the month of February after the presenter's personal associations came to light, and in July an internal BBC review concluded it infringed the corporation's editorial guidelines on truthfulness.
A representative for the broadcaster commented: "The Ofcom ruling is in line with the findings of the corporation's inquiry, that there was a serious error in the documentary in relation to the broadcaster's journalistic policies on factual correctness, which corresponds to regulation 2.2 of the regulator's media standards.
"We have apologised for this and we accept the regulator's ruling in complete. We will comply with the sanction as soon as the schedule and wording are finalised."
