The public service broadcaster committed a "major breach" of media regulations by failing to disclose that the voice of a documentary about the Gaza situation was the child of a Hamas representative, as determined by UK media regulator Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has determined that the programme was "materially misleading".
The BBC's director general had already issued an apology, stating there had been "a major oversight in relation to truthfulness".
The regulator has instructed the BBC to air a peak-time announcement about its findings.
"Since this amounts to a serious breach of our regulations, we are directing the corporation to air a statement of our determinations against it on BBC Two at 9pm, with a timing to be confirmed," the regulator stated.
'Possibility to Damage Trust'
The watchdog's announcement said: "The inquiry we conducted found that the documentary's failure to disclose that the narrator's father served in a post in the Hamas-administered government was significantly deceptive.
"This implied that the public did not have vital facts which may have been very significant to their judgment of the voice and the information he provided.
"Confidence is at the core of the bond between a media organization and its viewers, particularly for a public service broadcaster such as the British Broadcasting Corporation.
"This oversight had the potential to erode the significantly high degrees of trust that viewers would have placed in a documentary produced by the BBC about the Israel-Gaza war."
The programme was removed from the online platform in February after the presenter's personal associations were revealed, and in the month of July an internal BBC review concluded it infringed the organization's editorial guidelines on factual correctness.
A BBC spokesperson said: "The regulator's decision is in accordance with the results of Peter Johnston's review, that there was a serious error in the documentary in relation to the corporation's content standards on factual correctness, which reflects clause 2.2 of the regulator's media standards.
"We have apologised for this and we accept the regulator's ruling in full. We will comply with the sanction as soon as the date and wording are finalised."
