The BBC was found to have committed a "major breach" of industry standards by not revealing that the voice of a programme about Gaza was the son of a Hamas representative, according to UK media regulator Ofcom.
An probe by the media regulator into the programme Gaza: How to Survive a Warzone has found that the documentary was "substantially inaccurate".
The BBC's director general had already issued an apology, saying there had been "a major oversight in relation to factual correctness".
Ofcom has ordered the BBC to air a prime-time statement about its decisions.
"Since this amounts to a serious breach of our rules, we are instructing the broadcaster to broadcast a statement of our conclusions against it on the BBC's second channel at 9pm, with a schedule to be confirmed," it said.
'Potential to Undermine Confidence'
The watchdog's statement stated: "The inquiry we conducted found that the documentary's failure to disclose that the voice's parent served in a role in the Hamas-run government was materially misleading.
"Consequently that the viewers did not have essential details which may have been extremely pertinent to their evaluation of the voice and the details he presented.
"Confidence is at the core of the bond between a media organization and its audience, especially for a state-funded media outlet such as the public broadcaster.
"This error had the potential to erode the exceptionally strong amounts of credibility that audiences would have put in a documentary produced by the BBC about the Israel-Gaza war."
The programme was pulled from iPlayer in February after the presenter's familial connections emerged, and in this past July an corporation's own inquiry found it violated the corporation's content policies on accuracy.
A BBC spokesperson commented: "The Ofcom ruling is in accordance with the conclusions of the internal assessment, that there was a significant failing in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which aligns with regulation 2.2 of the regulator's media standards.
"We have apologised for this and we agree with Ofcom's decision in complete. We will adhere to the penalty as soon as the schedule and wording are finalised."
