The BBC was found to have committed a "major breach" of broadcasting rules by failing to disclose that the presenter of a documentary about Gaza was the offspring of a Hamas administrator, as ruled by British broadcasting authority Ofcom.
An inquiry by the broadcasting watchdog into Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The head of the BBC had earlier expressed regret, noting there had been "a significant failing in relation to factual correctness".
The regulator has directed the BBC to transmit a peak-time announcement about its conclusions.
"Since this amounts to a major infringement of our code, we are directing the broadcaster to broadcast a announcement of our findings against it on BBC Two at 9pm, with a schedule to be finalised," the statement read.
'Potential to Undermine Confidence'
The authority's statement said: "Our investigation concluded that the programme's failure to disclose that the voice's parent occupied a position in the Hamas-run administration was substantially inaccurate.
"It meant that the audience did not have critical information which may have been very significant to their evaluation of the voice and the information he presented.
"Confidence is at the center of the connection between a television network and its viewers, especially for a national broadcasting corporation such as the British Broadcasting Corporation.
"This error had the possibility to damage the significantly high levels of trust that viewers would have invested in a BBC factual programme about the Israel-Gaza war."
The programme was withdrawn from iPlayer in last February after the narrator's family links emerged, and in July an internal BBC review determined it violated the broadcaster's editorial guidelines on truthfulness.
A corporation official commented: "The regulator's decision is in agreement with the conclusions of Peter Johnston's review, that there was a significant failing in the documentary in relation to the corporation's content standards on factual correctness, which reflects Rule 2.2 of the regulator's media standards.
"We issued an apology for this and we agree with Ofcom's decision in its entirety. We will adhere to the directive as soon as the schedule and wording are finalised."
