The BBC committed a "significant breach" of broadcasting rules by failing to disclose that the voice of a programme about Gaza was the offspring of a Hamas administrator, as ruled by British broadcasting authority Ofcom.
An inquiry by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has found that the documentary was "materially misleading".
The BBC's director general had earlier expressed regret, saying there had been "a significant failing in relation to factual correctness".
The regulator has instructed the BBC to broadcast a prime-time announcement about its conclusions.
"As this represents a serious breach of our regulations, we are instructing the corporation to broadcast a announcement of our determinations against it on BBC Two at nine o'clock in the evening, with a date to be finalised," it said.
'Potential to Erode Confidence'
The regulator's report stated: "Our investigation concluded that the documentary's lack of disclosure that the narrator's parent served in a role in the Hamas-run authority was significantly deceptive.
"Consequently that the public did not have vital facts which may have been very significant to their assessment of the voice and the information he provided.
"Confidence is at the core of the relationship between a media organization and its public, notably for a state-funded media outlet such as the public broadcaster.
"This error had the possibility to undermine the significantly high amounts of credibility that viewers would have placed in a BBC factual programme about the Israel-Gaza war."
The documentary was removed from iPlayer in last February after the narrator's family links were revealed, and in the month of July an corporation's own inquiry determined it violated the organization's journalistic standards on truthfulness.
A representative for the broadcaster commented: "The regulator's decision is in line with the results of the corporation's inquiry, that there was a serious error in the documentary in relation to the broadcaster's journalistic policies on accuracy, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We issued an apology for this and we accept Ofcom's decision in full. We will comply with the directive as soon as the schedule and wording are finalised."
