The BBC committed a "significant breach" of broadcasting rules by not revealing that the voice of a documentary about the Gaza conflict was the son of a Hamas official, according to British broadcasting authority Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has determined that the programme was "significantly deceptive".
The chief executive of the broadcaster had earlier expressed regret, noting there had been "a serious error in relation to truthfulness".
The regulator has directed the corporation to air a evening declaration about its findings.
"Since this amounts to a significant violation of our code, we are ordering the BBC to transmit a announcement of our conclusions against it on the BBC's second channel at nine o'clock in the evening, with a schedule to be determined," it said.
'Risk to Erode Credibility'
The watchdog's report declared: "The inquiry we conducted found that the documentary's omission to reveal that the voice's father held a position in the Hamas-run authority was significantly deceptive.
"This implied that the public did not have essential details which may have been highly relevant to their assessment of the narrator and the content he presented.
"Confidence is at the core of the connection between a media organization and its viewers, especially for a state-funded media outlet such as the BBC.
"This failing had the possibility to undermine the exceptionally strong degrees of trust that viewers would have invested in a factual film from the broadcaster about the Israel-Gaza war."
The documentary was pulled from the online platform in February after the narrator's family links emerged, and in the month of July an corporation's own inquiry concluded it infringed the organization's journalistic standards on truthfulness.
A BBC spokesperson said: "The authority's determination is in line with the results of the internal assessment, that there was a major oversight in the film in relation to the BBC's Editorial Guidelines on accuracy, which aligns with clause 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with the authority's determination in its entirety. We will comply with the directive as soon as the schedule and wording are finalised."
