The public service broadcaster engaged in a "major breach" of broadcasting rules by omitting to mention that the presenter of a documentary about Gaza was the offspring of a Hamas official, according to regulatory body Ofcom.
An investigation by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has determined that the programme was "substantially inaccurate".
The BBC's director general had previously apologised, saying there had been "a major oversight in relation to truthfulness".
Ofcom has instructed the corporation to broadcast a prime-time declaration about its conclusions.
"Given this constitutes a major infringement of our code, we are instructing the BBC to transmit a announcement of our determinations against it on BBC2 at nine o'clock in the evening, with a schedule to be determined," the regulator stated.
'Risk to Undermine Confidence'
The watchdog's announcement stated: "Our probe determined that the programme's failure to disclose that the presenter's parent served in a role in the Hamas-administered authority was materially misleading.
"It meant that the audience did not have vital facts which may have been highly relevant to their assessment of the voice and the information he presented.
"Confidence is at the center of the connection between a television network and its viewers, notably for a public service broadcaster such as the British Broadcasting Corporation.
"This error had the potential to undermine the significantly high degrees of credibility that viewers would have put in a documentary produced by the BBC about the Gaza conflict."
The documentary was pulled from the online platform in last February after the presenter's familial connections were revealed, and in July an corporation's own inquiry determined it breached the corporation's editorial guidelines on truthfulness.
A BBC spokesperson stated: "The Ofcom ruling is in agreement with the results of Peter Johnston's review, that there was a serious error in the film in relation to the broadcaster's journalistic policies on accuracy, which aligns with regulation 2.2 of the regulator's media standards.
"We issued an apology for this and we accept the authority's determination in full. We will comply with the sanction as soon as the timing and language are finalised."
