The public service broadcaster committed a "serious breach" of broadcasting rules by omitting to mention that the voice of a documentary about Gaza was the offspring of a Hamas representative, as ruled by British broadcasting authority Ofcom.
An inquiry by Ofcom into Gaza: How to Survive a Warzone has found that the programme was "substantially inaccurate".
The BBC's director general had previously apologised, stating there had been "a serious error in relation to truthfulness".
The authority has ordered the corporation to transmit a evening declaration about its findings.
"Since this amounts to a major infringement of our code, we are directing the corporation to broadcast a statement of our conclusions against it on the BBC's second channel at 9pm, with a timing to be confirmed," it said.
'Risk to Erode Confidence'
The watchdog's statement stated: "Our investigation concluded that the documentary's omission to reveal that the voice's parent served in a role in the Hamas-run authority was significantly deceptive.
"Consequently that the viewers did not have essential details which may have been extremely pertinent to their judgment of the narrator and the content he presented.
"Credibility is at the center of the connection between a broadcaster and its public, notably for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the potential to damage the exceptionally strong amounts of credibility that the public would have put in a BBC factual programme about the Gaza conflict."
The programme was pulled from the online platform in last February after the presenter's familial connections emerged, and in this past July an broadcaster's internal assessment determined it infringed the corporation's journalistic standards on accuracy.
A BBC spokesperson stated: "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 factual correctness, which aligns with clause 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we agree with the regulator's ruling in full. We will follow the sanction as soon as the timing and wording are determined."
