The BBC committed a "major breach" of media regulations by failing to disclose that the voice of a documentary about the Gaza conflict was the offspring of a Hamas official, according to British broadcasting authority Ofcom.
An investigation by the media regulator into the programme Gaza: How to Survive a Warzone has concluded that the film was "substantially inaccurate".
The head of the BBC had previously apologised, saying there had been "a major oversight in relation to accuracy".
Ofcom has ordered the corporation to air a peak-time declaration about its decisions.
"As this represents a serious breach of our rules, we are directing the broadcaster to transmit a announcement of our conclusions against it on BBC Two at nine o'clock in the evening, with a date to be finalised," it said.
'Potential to Undermine Confidence'
The authority's announcement stated: "Our probe found that the documentary's failure to disclose that the narrator's parent served in a position in the Hamas-administered government was significantly deceptive.
"Consequently that the audience did not have vital facts which may have been very significant to their evaluation of the voice and the details he provided.
"Confidence is at the center of the relationship between a media organization and its viewers, particularly for a national broadcasting corporation such as the public broadcaster.
"This oversight had the potential to erode the very considerable levels of trust that audiences would have placed in a BBC factual programme about the Israel-Gaza war."
The documentary was pulled from the BBC's streaming service in last February after the presenter's personal associations came to light, and in the month of July an corporation's own inquiry concluded it breached the broadcaster's content policies on factual correctness.
A corporation official stated: "The regulator's decision is in agreement with the results of Peter Johnston's review, that there was a serious error in the documentary in relation to the broadcaster's journalistic policies on factual correctness, which reflects regulation 2.2 of the authority's broadcasting regulations.
"We have apologised for this and we agree with the regulator's ruling in full. We will follow the directive as soon as the date and wording are confirmed."
