The British broadcaster was found to have committed a "major breach" of industry standards by omitting to mention that the voice of a documentary about Gaza was the offspring of a Hamas official, as determined by British broadcasting authority Ofcom.
An probe by the media regulator into Gaza: How to Survive a Warzone has determined that the film was "significantly deceptive".
The head of the BBC had already issued an apology, stating there had been "a significant failing in relation to accuracy".
Ofcom has ordered the BBC to air a evening announcement about its decisions.
"Since this amounts to a major infringement of our rules, we are directing the BBC to transmit a message of our conclusions against it on BBC Two at nine o'clock in the evening, with a date to be confirmed," the statement read.
'Potential to Undermine Trust'
The authority's announcement said: "Our investigation found that the film's lack of disclosure that the presenter's parent served in a position in the Hamas-administered administration was materially misleading.
"Consequently that the public did not have critical information which may have been highly relevant to their evaluation of the narrator and the details he shared.
"Confidence is at the heart of the relationship between a media organization and its viewers, especially for a public service broadcaster such as the BBC.
"This failing had the possibility to damage the very considerable levels of confidence that viewers would have invested in a factual film from the broadcaster about the conflict in Gaza."
The programme was removed from iPlayer in last February after the presenter's familial connections were revealed, and in the month of July an broadcaster's internal assessment found it infringed the broadcaster's journalistic standards on accuracy.
A corporation official commented: "The regulator's decision is in accordance with the results of Peter Johnston's review, that there was a major oversight in the programme in relation to the corporation's content standards on accuracy, which corresponds to regulation 2.2 of the regulator's media standards.
"We expressed regret for this and we accept the regulator's ruling in its entirety. We will adhere to the sanction as soon as the date and wording are confirmed."
