The public service broadcaster engaged in a "major breach" of broadcasting rules by omitting to mention that the narrator of a programme about Gaza was the son of a Hamas official, according to British broadcasting authority Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has concluded that the film was "substantially inaccurate".
The BBC's director general had already issued an apology, saying there had been "a significant failing in relation to truthfulness".
Ofcom has directed the corporation to air a evening declaration about its decisions.
"Since this amounts to a serious breach of our rules, we are ordering the broadcaster to broadcast a message of our findings against it on BBC2 at nine o'clock in the evening, with a schedule to be confirmed," the regulator stated.
'Possibility to Erode Trust'
The regulator's statement declared: "The inquiry we conducted determined that the film's omission to reveal that the presenter's male guardian occupied a position in the Hamas-administered government was substantially inaccurate.
"Consequently that the public did not have essential details which may have been extremely pertinent to their assessment of the voice and the content he presented.
"Confidence is at the heart of the connection between a broadcaster and its viewers, especially for a national broadcasting corporation such as the BBC.
"This failing had the potential to damage the exceptionally strong levels of credibility that the public would have placed in a factual film from the broadcaster about the Gaza conflict."
The documentary was withdrawn from the online platform in February after the presenter's familial connections emerged, and in the month of July an corporation's own inquiry found it violated the broadcaster's content policies on factual correctness.
A BBC spokesperson commented: "The Ofcom ruling is in agreement with the conclusions of the corporation's inquiry, that there was a significant failing in the film in relation to the corporation's content standards on truthfulness, which corresponds to clause 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we accept the regulator's ruling in full. We will adhere to the penalty as soon as the timing and wording are confirmed."
