The British broadcaster engaged in a "significant breach" of broadcasting rules by not revealing that the narrator of a film about the Gaza situation was the offspring of a Hamas official, as ruled by UK media regulator Ofcom.
An inquiry by Ofcom into the documentary titled Gaza: How to Survive a Warzone has concluded that the programme was "materially misleading".
The BBC's director general had previously apologised, saying there had been "a serious error in relation to factual correctness".
Ofcom has instructed the BBC to transmit a peak-time announcement about its findings.
"Since this amounts to a serious breach of our rules, we are directing the corporation to transmit a announcement of our conclusions against it on BBC Two at nine o'clock in the evening, with a date to be finalised," it said.
'Risk to Undermine Trust'
The watchdog's announcement stated: "The inquiry we conducted found that the film's failure to disclose that the presenter's male guardian occupied a post in the Hamas-run government was substantially inaccurate.
"This implied that the viewers did not have vital facts which may have been highly relevant to their assessment of the voice and the information he shared.
"Trust is at the heart of the bond between a broadcaster and its viewers, notably for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the potential to damage the exceptionally strong levels of confidence that audiences would have put in a documentary produced by the BBC about the Gaza conflict."
The film was removed from the online platform in last February after the presenter's family links emerged, and in this past July an corporation's own inquiry determined it infringed the corporation's content policies on factual correctness.
A representative for the broadcaster said: "The regulator's decision is in accordance with the results of Peter Johnston's review, that there was a serious error in the film in relation to the corporation's content standards on accuracy, which aligns with Rule 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we comply with the authority's determination in its entirety. We will adhere to the penalty as soon as the schedule and wording are finalised."
