The public service broadcaster engaged in a "significant breach" of media regulations by not revealing that the presenter of a programme about the Gaza conflict was the child of a Hamas official, as determined by British broadcasting authority Ofcom.
An inquiry by the media regulator into the programme Gaza: How to Survive a Warzone has concluded that the film was "materially misleading".
The chief executive of the broadcaster had earlier expressed regret, saying there had been "a serious error in relation to truthfulness".
The authority has instructed the BBC to broadcast a evening declaration about its conclusions.
"Since this amounts to a significant violation of our regulations, we are instructing the BBC to air a announcement of our conclusions against it on the BBC's second channel at nine o'clock in the evening, with a schedule to be confirmed," the statement read.
'Potential to Damage Confidence'
The authority's report stated: "The inquiry we conducted concluded that the programme's failure to disclose that the narrator's male guardian held a position in the Hamas-administered administration was materially misleading.
"It meant that the viewers did not have essential details which may have been very significant to their judgment of the presenter and the details he presented.
"Trust is at the core of the relationship between a broadcaster and its viewers, notably for a state-funded media outlet such as the British Broadcasting Corporation.
"This oversight had the possibility to undermine the significantly high amounts of trust that viewers would have put in a factual film from the broadcaster about the Gaza conflict."
The documentary was pulled from iPlayer in February after the presenter's family links emerged, and in the month of July an corporation's own inquiry found it breached the corporation's journalistic standards on accuracy.
A representative for the broadcaster stated: "The Ofcom ruling is in accordance with the conclusions of Peter Johnston's review, that there was a serious error in the film in relation to the BBC's Editorial Guidelines on accuracy, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we comply with the regulator's ruling in full. We will follow the sanction as soon as the schedule and wording are determined."
