The British broadcaster engaged in a "significant breach" of broadcasting rules by omitting to mention that the presenter of a film about Gaza was the offspring of a Hamas administrator, as ruled by British broadcasting authority Ofcom.
An probe by Ofcom into the programme Gaza: How to Survive a Warzone has determined that the documentary was "materially misleading".
The head of the BBC had already issued an apology, saying there had been "a significant failing in relation to truthfulness".
The regulator has directed the broadcaster to transmit a peak-time announcement about its findings.
"As this represents a serious breach of our code, we are instructing the BBC to air a statement of our determinations against it on BBC Two at 9pm, with a timing to be determined," the regulator stated.
'Possibility to Undermine Credibility'
The regulator's announcement said: "The inquiry we conducted found that the film's lack of disclosure that the presenter's father occupied a position in the Hamas-controlled authority was substantially inaccurate.
"This implied that the audience did not have vital facts which may have been extremely pertinent to their judgment of the presenter and the content he presented.
"Trust is at the core of the bond between a broadcaster and its viewers, especially for a public service broadcaster such as the BBC.
"This failing had the risk to undermine the very considerable amounts of confidence that the public would have placed in a factual film from the broadcaster about the Gaza conflict."
The documentary was removed from iPlayer in last February after the narrator's family links emerged, and in July an corporation's own inquiry concluded it breached the organization's editorial guidelines on truthfulness.
A representative for the broadcaster said: "The Ofcom ruling is in agreement with the conclusions of Peter Johnston's review, that there was a significant failing in the documentary in relation to the corporation's content standards on accuracy, which aligns with Rule 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we agree with Ofcom's decision in its entirety. We will adhere to the sanction as soon as the timing and language are confirmed."
