The BBC committed a "major breach" of industry standards by failing to disclose that the voice of a programme about Gaza was the offspring of a Hamas administrator, as ruled by regulatory body Ofcom.
An investigation by Ofcom into the documentary titled Gaza: How to Survive a Warzone has determined that the film was "materially misleading".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a major oversight in relation to truthfulness".
Ofcom has directed the broadcaster to air a evening statement about its decisions.
"Since this amounts to a significant violation of our code, we are directing the broadcaster to broadcast a message of our conclusions against it on BBC Two at 21:00, with a schedule to be finalised," it said.
'Risk to Undermine Credibility'
The watchdog's announcement said: "The inquiry we conducted determined that the film's failure to disclose that the narrator's male guardian held a position in the Hamas-controlled authority was materially misleading.
"This implied that the public did not have vital facts which may have been extremely pertinent to their judgment of the narrator and the content he presented.
"Credibility is at the heart of the relationship between a broadcaster and its audience, particularly for a national broadcasting corporation such as the British Broadcasting Corporation.
"This error had the potential to undermine the significantly high degrees of trust that viewers would have put in a documentary produced by the BBC about the Israel-Gaza war."
The film was pulled from the BBC's streaming service in last February after the narrator's familial connections were revealed, and in this past July an broadcaster's internal assessment concluded it infringed the corporation's content policies on accuracy.
A representative for the broadcaster stated: "The regulator's decision is in line with the conclusions of Peter Johnston's review, that there was a major oversight in the film in relation to the corporation's content standards on truthfulness, which reflects Rule 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we comply with Ofcom's decision in full. We will follow the penalty as soon as the schedule and language are confirmed."
