The BBC committed a "major breach" of industry standards by omitting to mention that the narrator of a film about the Gaza situation was the offspring of a Hamas administrator, as determined by regulatory body Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has determined that the film was "substantially inaccurate".
The chief executive of the broadcaster had previously apologised, noting there had been "a major oversight in relation to truthfulness".
The authority has directed the corporation to broadcast a peak-time statement about its conclusions.
"Since this amounts to a major infringement of our rules, we are directing the corporation to broadcast a announcement of our determinations against it on BBC2 at 21:00, with a schedule to be determined," it said.
'Potential to Undermine Confidence'
The watchdog's announcement declared: "Our investigation determined that the programme's lack of disclosure that the voice's parent served in a post in the Hamas-administered administration was substantially inaccurate.
"This implied that the audience did not have critical information which may have been extremely pertinent to their assessment of the narrator and the information he provided.
"Trust is at the center of the connection between a media organization and its public, notably for a national broadcasting corporation such as the BBC.
"This error had the risk to erode the exceptionally strong amounts of credibility that audiences would have put in a factual film from the broadcaster about the Gaza conflict."
The documentary was withdrawn from the BBC's streaming service in last February after the narrator's personal associations came to light, and in this past July an broadcaster's internal assessment found it infringed the organization's content policies on accuracy.
A BBC spokesperson stated: "The regulator's decision is in accordance with the conclusions of the internal assessment, that there was a serious error in the film in relation to the broadcaster's journalistic policies on truthfulness, which aligns with clause 2.2 of Ofcom's Broadcasting Code.
"We expressed regret for this and we comply with the authority's determination in complete. We will follow the sanction as soon as the timing and language are finalised."
