The public service broadcaster engaged in a "serious breach" of broadcasting rules by failing to disclose that the voice of a documentary about the Gaza situation was the son of a Hamas representative, as determined by regulatory body Ofcom.
An inquiry by the media regulator into the documentary titled Gaza: How to Survive a Warzone has determined that the programme was "substantially inaccurate".
The BBC's director general had previously apologised, noting there had been "a major oversight in relation to accuracy".
Ofcom has ordered the broadcaster to air a evening announcement about its decisions.
"Since this amounts to a significant violation of our regulations, we are instructing the corporation to broadcast a message of our conclusions against it on BBC2 at 21:00, with a timing to be finalised," it said.
'Risk to Undermine Trust'
The watchdog's report declared: "Our probe concluded that the documentary's omission to reveal that the narrator's parent occupied a position in the Hamas-administered government was materially misleading.
"This implied that the public did not have vital facts which may have been very significant to their assessment of the narrator and the information he provided.
"Credibility is at the heart of the bond between a media organization and its viewers, notably for a state-funded media outlet such as the BBC.
"This oversight had the risk to erode the significantly high degrees of confidence that viewers would have invested in a factual film from the broadcaster about the conflict in Gaza."
The film was withdrawn from the online platform in February after the narrator's familial connections were revealed, and in July an corporation's own inquiry determined it infringed the broadcaster's content policies on truthfulness.
A corporation official said: "The authority's determination is in line with the conclusions of the internal assessment, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which reflects Rule 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we accept the authority's determination in its entirety. We will adhere to the penalty as soon as the timing and language are confirmed."
