The BBC engaged in a "serious breach" of media regulations by not revealing that the narrator of a film about the Gaza situation was the offspring of a Hamas official, as ruled by regulatory body Ofcom.
An probe by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The chief executive of the broadcaster had already issued an apology, saying there had been "a major oversight in relation to accuracy".
The authority has instructed the corporation to air a evening statement about its findings.
"As this represents a significant violation of our regulations, we are ordering the corporation to air a announcement of our findings against it on the BBC's second channel at nine o'clock in the evening, with a schedule to be determined," the regulator stated.
'Risk to Erode Confidence'
The authority's statement declared: "Our investigation found that the film's failure to disclose that the voice's male guardian held a role in the Hamas-run administration was substantially inaccurate.
"This implied that the viewers did not have critical information which may have been very significant to their assessment of the presenter and the information he provided.
"Credibility is at the center of the relationship between a television network and its public, notably for a national broadcasting corporation such as the British Broadcasting Corporation.
"This oversight had the possibility to damage the exceptionally strong amounts of credibility that audiences would have invested in a factual film from the broadcaster about the conflict in Gaza."
The programme was withdrawn from the BBC's streaming service in last February after the presenter's familial connections came to light, and in July an corporation's own inquiry found it infringed the corporation's journalistic standards on truthfulness.
A corporation official stated: "The regulator's decision is in line with the conclusions of Peter Johnston's review, that there was a significant failing in the film in relation to the corporation's content standards on factual correctness, which reflects regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we comply with Ofcom's decision in complete. We will follow the penalty as soon as the timing and wording are determined."
