The BBC engaged in a "significant breach" of industry standards by not revealing that the voice of a film about Gaza was the child of a Hamas representative, according to regulatory body Ofcom.
An inquiry by Ofcom into the documentary titled Gaza: How to Survive a Warzone has determined that the film was "significantly deceptive".
The BBC's director general had earlier expressed regret, saying there had been "a serious error in relation to factual correctness".
Ofcom has directed the broadcaster to broadcast a prime-time statement about its decisions.
"Given this constitutes a significant violation of our code, we are instructing the BBC to air a message of our determinations against it on BBC Two at nine o'clock in the evening, with a timing to be determined," the regulator stated.
'Risk to Damage Confidence'
The watchdog's report said: "Our investigation determined that the programme's omission to reveal that the narrator's parent served in a position in the Hamas-run administration was substantially inaccurate.
"This implied that the viewers did not have critical information which may have been highly relevant to their judgment of the voice and the content he presented.
"Trust is at the heart of the relationship between a media organization and its viewers, particularly for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the risk to erode the significantly high levels of confidence that audiences would have put in a BBC factual programme about the Israel-Gaza war."
The film was pulled from iPlayer in the month of February after the presenter's familial connections were revealed, and in this past July an corporation's own inquiry found it infringed the organization's editorial guidelines on factual correctness.
A corporation official said: "The regulator's decision is in line with the results of the internal assessment, that there was a major oversight in the programme in relation to the corporation's content standards on accuracy, which corresponds to regulation 2.2 of the authority's broadcasting regulations.
"We issued an apology for this and we comply with Ofcom's decision in full. We will follow the penalty as soon as the timing and wording are confirmed."
