The BBC engaged in a "significant breach" of media regulations by omitting to mention that the narrator of a film about the Gaza situation was the child of a Hamas official, as determined by regulatory body Ofcom.
An probe by the media regulator into the programme Gaza: How to Survive a Warzone has determined that the documentary was "significantly deceptive".
The BBC's director general had already issued an apology, saying there had been "a serious error in relation to accuracy".
Ofcom has directed the broadcaster to air a evening statement about its conclusions.
"Since this amounts to a major infringement of our code, we are directing the BBC to air a statement of our findings against it on BBC2 at 9pm, with a timing to be confirmed," it said.
'Risk to Damage Confidence'
The authority's announcement stated: "The inquiry we conducted concluded that the programme's lack of disclosure that the voice's male guardian occupied a position in the Hamas-run authority was significantly deceptive.
"This implied that the viewers did not have critical information which may have been highly relevant to their judgment of the presenter and the details he presented.
"Trust is at the heart of the bond between a media organization and its public, notably for a national broadcasting corporation such as the British Broadcasting Corporation.
"This error had the possibility to erode the significantly high levels of confidence that the public 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 familial connections came to light, and in July an broadcaster's internal assessment concluded it violated the organization's content policies on truthfulness.
A representative for the broadcaster commented: "The Ofcom ruling is in line with the results of the internal assessment, that there was a serious error in the film in relation to the BBC's Editorial Guidelines on truthfulness, which reflects regulation 2.2 of the regulator's media standards.
"We issued an apology for this and we agree with the authority's determination in its entirety. We will adhere to the sanction as soon as the timing and wording are finalised."
