The BBC committed a "significant breach" of industry standards by omitting to mention that the voice of a programme about the Gaza conflict was the son of a Hamas representative, as determined by British broadcasting authority Ofcom.
An probe by Ofcom into the documentary titled Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The BBC's director general had earlier expressed regret, noting there had been "a serious error in relation to accuracy".
The authority has instructed the BBC to transmit a evening announcement about its conclusions.
"Given this constitutes a significant violation of our regulations, we are ordering the corporation to air a announcement of our findings against it on BBC Two at 9pm, with a schedule to be confirmed," it said.
'Possibility to Damage Confidence'
The regulator's statement said: "The inquiry we conducted determined that the documentary's failure to disclose that the narrator's parent served in a post in the Hamas-administered government was substantially inaccurate.
"It meant that the audience did not have vital facts which may have been very significant to their evaluation of the narrator and the details he presented.
"Confidence is at the core of the bond between a television network and its viewers, particularly for a state-funded media outlet such as the BBC.
"This failing had the possibility to undermine the exceptionally strong degrees of credibility that viewers would have placed in a BBC factual programme about the Israel-Gaza war."
The documentary was removed from the BBC's streaming service in the month of February after the narrator's personal associations came to light, and in the month of July an broadcaster's internal assessment found it violated the corporation's content policies on factual correctness.
A corporation official stated: "The Ofcom ruling is in accordance with the findings of the corporation's inquiry, that there was a serious error in the programme in relation to the corporation's content standards on truthfulness, which corresponds to clause 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we accept the regulator's ruling in its entirety. We will comply with the penalty as soon as the schedule and wording are determined."
