The British broadcaster committed a "major breach" of media regulations by not revealing that the voice of a programme about the Gaza situation was the son of a Hamas official, according to British broadcasting authority Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has found that the documentary was "materially misleading".
The BBC's director general had earlier expressed regret, noting there had been "a significant failing in relation to truthfulness".
The authority has ordered the broadcaster to broadcast a prime-time declaration about its decisions.
"Given this constitutes a major infringement of our code, we are ordering the corporation to transmit a statement of our conclusions against it on BBC2 at 21:00, with a date to be finalised," it said.
'Potential to Erode Confidence'
The regulator's statement stated: "The inquiry we conducted found that the programme's failure to disclose that the narrator's father occupied a role in the Hamas-controlled administration was materially misleading.
"Consequently that the public did not have essential details which may have been highly relevant to their judgment of the narrator and the details he provided.
"Confidence is at the center of the connection between a television network and its public, notably for a public service broadcaster such as the BBC.
"This failing had the potential to undermine the very considerable levels of confidence that audiences would have invested in a BBC factual programme about the Gaza conflict."
The programme was removed from iPlayer in last February after the presenter's personal associations emerged, and in the month of July an corporation's own inquiry determined it breached the corporation's editorial guidelines on truthfulness.
A representative for the broadcaster said: "The authority's determination is in accordance with the conclusions of Peter Johnston's review, that there was a major oversight in the documentary in relation to the broadcaster's journalistic policies on factual correctness, which reflects Rule 2.2 of the authority's broadcasting regulations.
"We expressed regret for this and we accept the regulator's ruling in complete. We will follow the penalty as soon as the timing and wording are confirmed."
