The British broadcaster engaged in a "major breach" of industry standards by omitting to mention that the narrator of a documentary about the Gaza situation was the offspring of a Hamas administrator, according to regulatory body Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has concluded that the film was "materially misleading".
The head of the BBC had earlier expressed regret, saying there had been "a significant failing in relation to truthfulness".
The authority has directed the BBC to broadcast a evening announcement about its conclusions.
"As this represents a serious breach of our rules, we are instructing the BBC to transmit a statement of our findings against it on BBC Two at 21:00, with a schedule to be finalised," it said.
'Possibility to Undermine Confidence'
The authority's report stated: "Our investigation found that the documentary's lack of disclosure that the voice's male guardian held a post in the Hamas-administered administration was significantly deceptive.
"It meant that the viewers did not have vital facts which may have been very significant to their judgment of the narrator and the details he provided.
"Credibility is at the core of the bond between a television network and its viewers, notably for a national broadcasting corporation such as the BBC.
"This failing had the potential to undermine the exceptionally strong amounts of trust that the public would have invested in a factual film from the broadcaster about the Gaza conflict."
The film was removed from the online platform in the month of February after the narrator's personal associations were revealed, and in this past July an corporation's own inquiry concluded it breached the organization's content policies on accuracy.
A BBC spokesperson stated: "The regulator's decision is in line with the results of the corporation's inquiry, that there was a significant failing in the documentary in relation to the broadcaster's journalistic policies on truthfulness, which reflects Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we comply with the regulator's ruling in its entirety. We will follow the penalty as soon as the date and language are determined."
