The public service broadcaster committed a "serious breach" of broadcasting rules by not revealing that the voice of a film about Gaza was the offspring of a Hamas representative, as ruled by British broadcasting authority Ofcom.
An inquiry by Ofcom into the programme Gaza: How to Survive a Warzone has concluded that the programme was "materially misleading".
The BBC's director general had earlier expressed regret, noting there had been "a major oversight in relation to accuracy".
Ofcom has instructed the BBC to broadcast a peak-time declaration about its decisions.
"Given this constitutes a serious breach of our code, we are directing the BBC to broadcast a announcement of our findings against it on BBC Two at nine o'clock in the evening, with a date to be determined," the regulator stated.
'Possibility to Damage Credibility'
The regulator's announcement declared: "Our investigation concluded that the programme's failure to disclose that the narrator's father served in a position in the Hamas-run authority was substantially inaccurate.
"Consequently that the public did not have vital facts which may have been very significant to their judgment of the presenter and the content he provided.
"Confidence is at the core of the relationship between a television network and its viewers, particularly for a state-funded media outlet such as the BBC.
"This oversight had the potential to undermine the exceptionally strong amounts of credibility that viewers would have invested in a documentary produced by the BBC about the Israel-Gaza war."
The film was removed from the BBC's streaming service in last February after the narrator's familial connections came to light, and in this past July an internal BBC review concluded it infringed the corporation's content policies on truthfulness.
A BBC spokesperson commented: "The Ofcom ruling is in agreement with the findings of Peter Johnston's review, that there was a significant failing in the documentary in relation to the broadcaster's journalistic policies on truthfulness, which reflects clause 2.2 of the regulator's media standards.
"We issued an apology for this and we agree with the authority's determination in full. We will follow the directive as soon as the schedule and wording are finalised."
