The BBC committed a "serious breach" of media regulations by omitting to mention that the presenter of a programme about Gaza was the offspring of a Hamas official, according to UK media regulator Ofcom.
An probe by the broadcasting watchdog into the documentary titled Gaza: How to Survive a Warzone has found that the film was "substantially inaccurate".
The head of the BBC had earlier expressed regret, saying there had been "a major oversight in relation to accuracy".
Ofcom has ordered the broadcaster to broadcast a peak-time declaration about its conclusions.
"As this represents a serious breach of our code, we are ordering the corporation to air a statement of our determinations against it on BBC Two at nine o'clock in the evening, with a timing to be determined," the statement read.
'Potential to Damage Confidence'
The regulator's statement stated: "Our probe determined that the documentary's lack of disclosure that the presenter's male guardian occupied a position in the Hamas-controlled administration was substantially inaccurate.
"It meant that the public did not have vital facts which may have been highly relevant to their evaluation of the presenter and the information he presented.
"Confidence is at the heart of the bond between a media organization and its public, notably for a public service broadcaster such as the BBC.
"This failing had the risk to damage the exceptionally strong levels of credibility that the public would have placed in a documentary produced by the BBC about the conflict in Gaza."
The programme was pulled from the online platform in last February after the narrator's familial connections came to light, and in the month of July an internal BBC review concluded it breached the organization's journalistic standards on truthfulness.
A representative for the broadcaster said: "The regulator's decision is in agreement with the conclusions of the internal assessment, that there was a significant failing 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 expressed regret for this and we accept the regulator's ruling in its entirety. We will comply with the sanction as soon as the schedule and language are finalised."
