The British broadcaster was found to have committed a "major breach" of industry standards by not revealing that the voice of a documentary about the Gaza conflict was the son of a Hamas official, as ruled by regulatory body Ofcom.
An inquiry by Ofcom into the programme Gaza: How to Survive a Warzone has determined that the film was "significantly deceptive".
The BBC's director general had already issued an apology, noting there had been "a major oversight in relation to truthfulness".
Ofcom has ordered the corporation to transmit a evening announcement about its findings.
"Since this amounts to a serious breach of our code, we are ordering the BBC to broadcast a announcement of our findings against it on the BBC's second channel at 9pm, with a date to be confirmed," the statement read.
'Possibility to Erode Credibility'
The watchdog's statement said: "The inquiry we conducted found that the documentary's lack of disclosure that the voice's parent served in a post in the Hamas-administered authority was materially misleading.
"This implied that the public did not have critical information which may have been highly relevant to their judgment of the voice and the content he presented.
"Trust is at the heart of the bond between a broadcaster and its public, notably for a national broadcasting corporation such as the BBC.
"This error had the potential to undermine the exceptionally strong levels of confidence that viewers would have invested in a factual film from the broadcaster about the Israel-Gaza war."
The film was withdrawn from the BBC's streaming service in last February after the presenter's family links emerged, and in this past July an corporation's own inquiry concluded it infringed the organization's content policies on factual correctness.
A representative for the broadcaster stated: "The regulator's decision is in agreement with the results of Peter Johnston's review, that there was a major oversight in the documentary in relation to the corporation's content standards on truthfulness, which reflects regulation 2.2 of the regulator's media standards.
"We have apologised for this and we accept the regulator's ruling in its entirety. We will adhere to the sanction as soon as the timing and wording are determined."
