The BBC was found to have committed a "serious breach" of media regulations by failing to disclose that the presenter of a programme about the Gaza conflict was the son of a Hamas administrator, according to regulatory body Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has determined that the programme was "significantly deceptive".
The head of the BBC had already issued an apology, noting there had been "a serious error in relation to truthfulness".
The regulator has instructed the broadcaster to air a prime-time declaration about its findings.
"As this represents a significant violation of our regulations, we are instructing the broadcaster to air a statement of our determinations against it on BBC2 at 9pm, with a schedule to be determined," the statement read.
'Potential to Damage Credibility'
The regulator's report stated: "The inquiry we conducted determined that the documentary's failure to disclose that the narrator's parent occupied a position in the Hamas-run authority was substantially inaccurate.
"This implied that the public did not have critical information which may have been highly relevant to their assessment of the presenter and the details he presented.
"Trust is at the core of the connection between a television network and its viewers, notably for a national broadcasting corporation such as the BBC.
"This failing had the possibility to undermine the exceptionally strong amounts of confidence that the public would have put in a documentary produced by the BBC about the conflict in Gaza."
The documentary was pulled from the BBC's streaming service in last February after the narrator's personal associations came to light, and in July an corporation's own inquiry determined it breached the organization's journalistic standards on truthfulness.
A corporation official stated: "The Ofcom ruling is in agreement with the findings 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 corresponds to Rule 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we comply with Ofcom's decision in full. We will follow the sanction as soon as the timing and language are confirmed."
