The BBC was found to have committed a "significant breach" of media regulations by failing to disclose that the presenter of a documentary about the Gaza conflict was the child of a Hamas administrator, as ruled by regulatory body Ofcom.
An inquiry by Ofcom into the programme Gaza: How to Survive a Warzone has determined that the film was "substantially inaccurate".
The BBC's director general had earlier expressed regret, noting there had been "a significant failing in relation to truthfulness".
Ofcom has directed the BBC to air a peak-time declaration about its conclusions.
"As this represents a significant violation of our code, we are directing the broadcaster to air a message of our conclusions against it on BBC2 at nine o'clock in the evening, with a timing to be finalised," it said.
'Risk to Undermine Confidence'
The watchdog's report stated: "Our investigation determined that the programme's lack of disclosure that the narrator's parent occupied a post in the Hamas-administered government was substantially inaccurate.
"This implied that the audience did not have critical information which may have been very significant to their judgment of the narrator and the information he shared.
"Credibility is at the core of the connection between a television network and its public, notably for a state-funded media outlet such as the BBC.
"This failing had the potential to undermine the significantly high amounts of trust that viewers would have invested in a BBC factual programme about the Israel-Gaza war."
The film was removed from iPlayer in the month of February after the presenter's familial connections came to light, and in this past July an broadcaster's internal assessment concluded it infringed the corporation's editorial guidelines on factual correctness.
A representative for the broadcaster commented: "The Ofcom ruling is in line with the results of the internal assessment, that there was a serious error in the film in relation to the BBC's Editorial Guidelines on truthfulness, which corresponds to Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we agree with Ofcom's decision in full. We will adhere to the penalty as soon as the timing and language are finalised."
