The BBC committed a "major breach" of broadcasting rules by failing to disclose that the presenter of a film about Gaza was the son of a Hamas administrator, as determined by British broadcasting authority Ofcom.
An investigation by the media regulator into Gaza: How to Survive a Warzone has found that the film was "substantially inaccurate".
The BBC's director general had earlier expressed regret, saying there had been "a major oversight in relation to accuracy".
The authority has instructed the broadcaster to transmit a evening declaration about its conclusions.
"As this represents a significant violation of our code, we are ordering the broadcaster to transmit a announcement of our determinations against it on BBC Two at 21:00, with a date to be determined," the regulator stated.
'Risk to Damage Confidence'
The regulator's statement stated: "The inquiry we conducted found that the documentary's failure to disclose that the narrator's parent occupied a post in the Hamas-administered government was materially misleading.
"It meant that the public did not have essential details which may have been very significant to their assessment of the narrator and the information he provided.
"Trust is at the heart of the bond between a broadcaster and its public, particularly for a national broadcasting corporation such as the British Broadcasting Corporation.
"This error had the possibility to erode the significantly high levels of credibility that audiences 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 narrator's familial connections were revealed, and in July an broadcaster's internal assessment determined it breached the broadcaster's journalistic standards on factual correctness.
A representative for the broadcaster said: "The authority's determination is in line with the conclusions of the corporation's inquiry, that there was a significant failing in the programme in relation to the corporation's content standards on truthfulness, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we comply with the authority's determination in full. We will adhere to the directive as soon as the schedule and wording are finalised."
