The BBC was found to have committed a "serious breach" of industry standards by omitting to mention that the narrator of a documentary about Gaza was the son of a Hamas administrator, as determined by British broadcasting authority Ofcom.
An inquiry by the media regulator into Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The head of the BBC had earlier expressed regret, stating there had been "a major oversight in relation to truthfulness".
The authority has instructed the BBC to broadcast a peak-time statement about its findings.
"Given this constitutes a significant violation of our rules, we are directing the corporation to air a message of our findings against it on BBC2 at 21:00, with a timing to be determined," the regulator stated.
'Possibility to Undermine Credibility'
The watchdog's statement stated: "Our probe determined that the film's omission to reveal that the narrator's male guardian held a role in the Hamas-run government was substantially inaccurate.
"This implied that the viewers did not have essential details which may have been very significant to their evaluation of the voice and the information he presented.
"Confidence is at the heart of the relationship between a television network and its audience, particularly for a public service broadcaster such as the public broadcaster.
"This oversight had the potential to damage the exceptionally strong amounts of credibility that viewers would have put in a BBC factual programme about the Gaza conflict."
The programme was withdrawn from the BBC's streaming service in last February after the presenter's personal associations emerged, and in July an internal BBC review found it infringed the broadcaster's editorial guidelines on accuracy.
A BBC spokesperson said: "The regulator's decision is in line with the conclusions of Peter Johnston's review, that there was a major oversight in the film in relation to the corporation's content standards on truthfulness, which aligns with regulation 2.2 of the regulator's media standards.
"We have apologised for this and we agree with the regulator's ruling in complete. We will comply with the directive as soon as the timing and wording are finalised."
