The BBC committed a "major breach" of broadcasting rules by failing to disclose that the presenter of a programme about Gaza was the offspring of a Hamas official, as ruled by regulatory body Ofcom.
An probe by the media regulator into Gaza: How to Survive a Warzone has found that the programme was "materially misleading".
The chief executive of the broadcaster had previously apologised, stating there had been "a major oversight in relation to factual correctness".
Ofcom has ordered the BBC to transmit a peak-time declaration about its findings.
"Since this amounts to a significant violation of our code, we are directing the broadcaster to transmit a announcement of our findings against it on BBC2 at 9pm, with a schedule to be finalised," it said.
'Possibility to Undermine Trust'
The authority's report declared: "Our investigation concluded that the film's omission to reveal that the narrator's father served in a position in the Hamas-administered authority was materially misleading.
"Consequently that the audience did not have vital facts which may have been highly relevant to their judgment of the presenter and the information he presented.
"Credibility is at the core of the relationship between a broadcaster and its viewers, especially for a public service broadcaster such as the British Broadcasting Corporation.
"This oversight had the potential to erode the exceptionally strong degrees of credibility that the public would have placed in a BBC factual programme about the Gaza conflict."
The programme was withdrawn from iPlayer in February after the presenter's familial connections came to light, and in this past July an broadcaster's internal assessment found it infringed the broadcaster's journalistic standards on accuracy.
A corporation official commented: "The regulator's decision is in line with the results of the corporation's inquiry, that there was a major oversight in the film in relation to the corporation's content standards on truthfulness, which corresponds to regulation 2.2 of the regulator's media standards.
"We have apologised for this and we comply with the regulator's ruling in complete. We will adhere to the sanction as soon as the timing and wording are confirmed."
