The BBC committed a "significant breach" of industry standards by omitting to mention that the narrator of a documentary about the Gaza conflict was the son of a Hamas administrator, according to regulatory body Ofcom.
An probe by Ofcom into Gaza: How to Survive a Warzone has determined that the film was "substantially inaccurate".
The BBC's director general had already issued an apology, saying there had been "a serious error in relation to truthfulness".
The regulator has directed the BBC to transmit a prime-time declaration about its decisions.
"Given this constitutes a significant violation of our regulations, we are ordering the broadcaster to air a statement of our determinations against it on the BBC's second channel at nine o'clock in the evening, with a date to be confirmed," the statement read.
'Potential to Erode Confidence'
The regulator's announcement said: "Our probe determined that the documentary's omission to reveal that the narrator's parent held a role in the Hamas-run authority was materially misleading.
"Consequently that the viewers did not have critical information which may have been extremely pertinent to their judgment of the narrator and the information he provided.
"Credibility is at the center of the relationship between a media organization and its public, notably for a national broadcasting corporation such as the BBC.
"This oversight had the possibility to erode the significantly high levels of credibility that the public would have placed in a documentary produced by the BBC about the Israel-Gaza war."
The programme was withdrawn from the online platform in last February after the presenter's familial connections came to light, and in the month of July an corporation's own inquiry concluded it violated the organization's journalistic standards on truthfulness.
A representative for the broadcaster said: "The regulator's decision is in accordance with the conclusions of Peter Johnston's review, that there was a major oversight in the film in relation to the BBC's Editorial Guidelines on truthfulness, which reflects clause 2.2 of the regulator's media standards.
"We have apologised for this and we agree with the authority's determination in full. We will comply with the directive as soon as the timing and language are finalised."
