The public service broadcaster engaged in a "serious breach" of broadcasting rules by failing to disclose that the presenter of a programme about the Gaza situation was the son of a Hamas official, according to UK media regulator Ofcom.
An inquiry by the media regulator into the programme Gaza: How to Survive a Warzone has determined that the film was "substantially inaccurate".
The head of the BBC had already issued an apology, stating there had been "a major oversight in relation to truthfulness".
Ofcom has instructed the corporation to broadcast a peak-time announcement about its conclusions.
"Given this constitutes a significant violation of our rules, we are instructing the broadcaster to transmit a announcement of our findings against it on the BBC's second channel at 9pm, with a schedule to be finalised," it said.
'Potential to Undermine Credibility'
The watchdog's report stated: "Our investigation concluded that the film's failure to disclose that the narrator's male guardian occupied a role in the Hamas-administered administration was materially misleading.
"Consequently that the audience did not have essential details which may have been extremely pertinent to their judgment of the voice and the details he presented.
"Credibility is at the center of the relationship between a television network and its public, particularly for a state-funded media outlet such as the BBC.
"This error had the potential to damage the very considerable degrees of confidence that the public would have put in a documentary produced by the BBC about the Israel-Gaza war."
The film was pulled from iPlayer in last February after the presenter's personal associations came to light, and in July an internal BBC review concluded it infringed the organization's editorial guidelines on accuracy.
A BBC spokesperson said: "The regulator's decision is in accordance with the findings of the internal assessment, that there was a significant failing in the programme in relation to the BBC's Editorial Guidelines on factual correctness, which corresponds to clause 2.2 of the regulator's media standards.
"We issued an apology for this and we accept the regulator's ruling in full. We will follow the sanction as soon as the schedule and wording are determined."
