The BBC engaged in a "significant breach" of broadcasting rules by not revealing that the narrator of a film about the Gaza situation was the offspring of a Hamas official, as determined by regulatory body Ofcom.
An investigation by Ofcom into Gaza: How to Survive a Warzone has concluded that the film was "significantly deceptive".
The BBC's director general had earlier expressed regret, noting there had been "a major oversight in relation to truthfulness".
The regulator has ordered the BBC to air a prime-time declaration about its decisions.
"Given this constitutes a significant violation of our regulations, we are directing the BBC to air a announcement of our determinations against it on the BBC's second channel at 21:00, with a schedule to be determined," the statement read.
'Potential to Undermine Trust'
The watchdog's announcement said: "Our probe concluded that the film's lack of disclosure that the voice's parent served in a role in the Hamas-run government was substantially inaccurate.
"This implied that the public did not have critical information which may have been very significant to their evaluation of the narrator and the information he shared.
"Credibility is at the heart of the relationship between a television network and its public, particularly for a national broadcasting corporation such as the British Broadcasting Corporation.
"This failing had the potential to undermine the significantly high amounts of confidence that the public would have invested in a factual film from the broadcaster about the conflict in Gaza."
The film was removed from the online platform in last February after the presenter's family links were revealed, and in July an corporation's own inquiry determined it infringed the organization's journalistic standards on factual correctness.
A corporation official commented: "The regulator's decision is in agreement with the findings of the corporation's inquiry, that there was a significant failing in the programme in relation to the broadcaster's journalistic policies on accuracy, which corresponds to Rule 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we comply with Ofcom's decision in complete. We will comply with the directive as soon as the timing and wording are confirmed."
